text: (function (global, factory) {
      typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
      typeof define === 'function' && define.amd ? define(['exports'], factory) :
      (factory((global.async = {})));
  }(this, (function (exports) { 'use strict';
  
      /**
       * Creates a continuation function with some arguments already applied.
       *
       * Useful as a shorthand when combined with other control flow functions. Any
       * arguments passed to the returned function are added to the arguments
       * originally passed to apply.
       *
       * @name apply
       * @static
       * @memberOf module:Utils
       * @method
       * @category Util
       * @param {Function} fn - The function you want to eventually apply all
       * arguments to. Invokes with (arguments...).
       * @param {...*} arguments... - Any number of arguments to automatically apply
       * when the continuation is called.
       * @returns {Function} the partially-applied function
       * @example
       *
       * // using apply
       * async.parallel([
       *     async.apply(fs.writeFile, 'testfile1', 'test1'),
       *     async.apply(fs.writeFile, 'testfile2', 'test2')
       * ]);
       *
       *
       * // the same process without using apply
       * async.parallel([
       *     function(callback) {
       *         fs.writeFile('testfile1', 'test1', callback);
       *     },
       *     function(callback) {
       *         fs.writeFile('testfile2', 'test2', callback);
       *     }
       * ]);
       *
       * // It's possible to pass any number of additional arguments when calling the
       * // continuation:
       *
       * node> var fn = async.apply(sys.puts, 'one');
       * node> fn('two', 'three');
       * one
       * two
       * three
       */
      function apply(fn, ...args) {
          return (...callArgs) => fn(...args,...callArgs);
      }
  
      function initialParams (fn) {
          return function (...args/*, callback*/) {
              var callback = args.pop();
              return fn.call(this, args, callback);
          };
      }
  
      var hasSetImmediate = typeof setImmediate === 'function' && setImmediate;
      var hasNextTick = typeof process === 'object' && typeof process.nextTick === 'function';
  
      function fallback(fn) {
          setTimeout(fn, 0);
      }
  
      function wrap(defer) {
          return (fn, ...args) => defer(() => fn(...args));
      }
  
      var _defer;
  
      if (hasSetImmediate) {
          _defer = setImmediate;
      } else if (hasNextTick) {
          _defer = process.nextTick;
      } else {
          _defer = fallback;
      }
  
      var setImmediate$1 = wrap(_defer);
  
      /**
       * Take a sync function and make it async, passing its return value to a
       * callback. This is useful for plugging sync functions into a waterfall,
       * series, or other async functions. Any arguments passed to the generated
       * function will be passed to the wrapped function (except for the final
       * callback argument). Errors thrown will be passed to the callback.
       *
       * If the function passed to `asyncify` returns a Promise, that promises's
       * resolved/rejected state will be used to call the callback, rather than simply
       * the synchronous return value.
       *
       * This also means you can asyncify ES2017 `async` functions.
       *
       * @name asyncify
       * @static
       * @memberOf module:Utils
       * @method
       * @alias wrapSync
       * @category Util
       * @param {Function} func - The synchronous function, or Promise-returning
       * function to convert to an {@link AsyncFunction}.
       * @returns {AsyncFunction} An asynchronous wrapper of the `func`. To be
       * invoked with `(args..., callback)`.
       * @example
       *
       * // passing a regular synchronous function
       * async.waterfall([
       *     async.apply(fs.readFile, filename, "utf8"),
       *     async.asyncify(JSON.parse),
       *     function (data, next) {
       *         // data is the result of parsing the text.
       *         // If there was a parsing error, it would have been caught.
       *     }
       * ], callback);
       *
       * // passing a function returning a promise
       * async.waterfall([
       *     async.apply(fs.readFile, filename, "utf8"),
       *     async.asyncify(function (contents) {
       *         return db.model.create(contents);
       *     }),
       *     function (model, next) {
       *         // `model` is the instantiated model object.
       *         // If there was an error, this function would be skipped.
       *     }
       * ], callback);
       *
       * // es2017 example, though `asyncify` is not needed if your JS environment
       * // supports async functions out of the box
       * var q = async.queue(async.asyncify(async function(file) {
       *     var intermediateStep = await processFile(file);
       *     return await somePromise(intermediateStep)
       * }));
       *
       * q.push(files);
       */
      function asyncify(func) {
          if (isAsync(func)) {
              return function (...args/*, callback*/) {
                  const callback = args.pop();
                  const promise = func.apply(this, args);
                  return handlePromise(promise, callback)
              }
          }
  
          return initialParams(function (args, callback) {
              var result;
              try {
                  result = func.apply(this, args);
              } catch (e) {
                  return callback(e);
              }
              // if result is Promise object
              if (result && typeof result.then === 'function') {
                  return handlePromise(result, callback)
              } else {
                  callback(null, result);
              }
          });
      }
  
      function handlePromise(promise, callback) {
          return promise.then(value => {
              invokeCallback(callback, null, value);
          }, err => {
              invokeCallback(callback, err && err.message ? err : new Error(err));
          });
      }
  
      function invokeCallback(callback, error, value) {
          try {
              callback(error, value);
          } catch (err) {
              setImmediate$1(e => { throw e }, err);
          }
      }
  
      function isAsync(fn) {
          return fn[Symbol.toStringTag] === 'AsyncFunction';
      }
  
      function isAsyncGenerator(fn) {
          return fn[Symbol.toStringTag] === 'AsyncGenerator';
      }
  
      function isAsyncIterable(obj) {
          return typeof obj[Symbol.asyncIterator] === 'function';
      }
  
      function wrapAsync(asyncFn) {
          if (typeof asyncFn !== 'function') throw new Error('expected a function')
          return isAsync(asyncFn) ? asyncify(asyncFn) : asyncFn;
      }
  
      // conditionally promisify a function.
      // only return a promise if a callback is omitted
      function awaitify (asyncFn, arity = asyncFn.length) {
          if (!arity) throw new Error('arity is undefined')
          function awaitable (...args) {
              if (typeof args[arity - 1] === 'function') {
                  return asyncFn.apply(this, args)
              }
  
              return new Promise((resolve, reject) => {
                  args[arity - 1] = (err, ...cbArgs) => {
                      if (err) return reject(err)
                      resolve(cbArgs.length > 1 ? cbArgs : cbArgs[0]);
                  };
                  asyncFn.apply(this, args);
              })
          }
  
          Object.defineProperty(awaitable, 'name', {
              value: `awaitable(${asyncFn.name})`
          });
  
          return awaitable
      }
  
      function applyEach (eachfn) {
          return function applyEach(fns, ...callArgs) {
              const go = awaitify(function (callback) {
                  var that = this;
                  return eachfn(fns, (fn, cb) => {
                      wrapAsync(fn).apply(that, callArgs.concat(cb));
                  }, callback);
              });
              return go;
          };
      }
  
      function _asyncMap(eachfn, arr, iteratee, callback) {
          arr = arr || [];
          var results = [];
          var counter = 0;
          var _iteratee = wrapAsync(iteratee);
  
          return eachfn(arr, (value, _, iterCb) => {
              var index = counter++;
              _iteratee(value, (err, v) => {
                  results[index] = v;
                  iterCb(err);
              });
          }, err => {
              callback(err, results);
          });
      }
  
      function isArrayLike(value) {
          return value &&
              typeof value.length === 'number' &&
              value.length >= 0 &&
              value.length % 1 === 0;
      }
  
      // A temporary value used to identify if the loop should be broken.
      // See #1064, #1293
      const breakLoop = {};
  
      function once(fn) {
          function wrapper (...args) {
              if (fn === null) return;
              var callFn = fn;
              fn = null;
              callFn.apply(this, args);
          }
          Object.assign(wrapper, fn);
          return wrapper
      }
  
      function getIterator (coll) {
          return coll[Symbol.iterator] && coll[Symbol.iterator]();
      }
  
      function createArrayIterator(coll) {
          var i = -1;
          var len = coll.length;
          return function next() {
              return ++i < len ? {value: coll[i], key: i} : null;
          }
      }
  
      function createES2015Iterator(iterator) {
          var i = -1;
          return function next() {
              var item = iterator.next();
              if (item.done)
                  return null;
              i++;
              return {value: item.value, key: i};
          }
      }
  
      function createObjectIterator(obj) {
          var okeys = obj ? Object.keys(obj) : [];
          var i = -1;
          var len = okeys.length;
          return function next() {
              var key = okeys[++i];
              return i < len ? {value: obj[key], key} : null;
          };
      }
  
      function createIterator(coll) {
          if (isArrayLike(coll)) {
              return createArrayIterator(coll);
          }
  
          var iterator = getIterator(coll);
          return iterator ? createES2015Iterator(iterator) : createObjectIterator(coll);
      }
  
      function onlyOnce(fn) {
          return function (...args) {
              if (fn === null) throw new Error("Callback was already called.");
              var callFn = fn;
              fn = null;
              callFn.apply(this, args);
          };
      }
  
      // for async generators
      function asyncEachOfLimit(generator, limit, iteratee, callback) {
          let done = false;
          let canceled = false;
          let awaiting = false;
          let running = 0;
          let idx = 0;
  
          function replenish() {
              //console.log('replenish')
              if (running >= limit || awaiting || done) return
              //console.log('replenish awaiting')
              awaiting = true;
              generator.next().then(({value, done: iterDone}) => {
                  //console.log('got value', value)
                  if (canceled || done) return
                  awaiting = false;
                  if (iterDone) {
                      done = true;
                      if (running <= 0) {
                          //console.log('done nextCb')
                          callback(null);
                      }
                      return;
                  }
                  running++;
                  iteratee(value, idx, iterateeCallback);
                  idx++;
                  replenish();
              }).catch(handleError);
          }
  
          function iterateeCallback(err, result) {
              //console.log('iterateeCallback')
              running -= 1;
              if (canceled) return
              if (err) return handleError(err)
  
              if (err === false) {
                  done = true;
                  canceled = true;
                  return
              }
  
              if (result === breakLoop || (done && running <= 0)) {
                  done = true;
                  //console.log('done iterCb')
                  return callback(null);
              }
              replenish();
          }
  
          function handleError(err) {
              if (canceled) return
              awaiting = false;
              done = true;
              callback(err);
          }
  
          replenish();
      }
  
      var eachOfLimit = (limit) => {
          return (obj, iteratee, callback) => {
              callback = once(callback);
              if (limit <= 0) {
                  throw new RangeError('concurrency limit cannot be less than 1')
              }
              if (!obj) {
                  return callback(null);
              }
              if (isAsyncGenerator(obj)) {
                  return asyncEachOfLimit(obj, limit, iteratee, callback)
              }
              if (isAsyncIterable(obj)) {
                  return asyncEachOfLimit(obj[Symbol.asyncIterator](), limit, iteratee, callback)
              }
              var nextElem = createIterator(obj);
              var done = false;
              var canceled = false;
              var running = 0;
              var looping = false;
  
              function iterateeCallback(err, value) {
                  if (canceled) return
                  running -= 1;
                  if (err) {
                      done = true;
                      callback(err);
                  }
                  else if (err === false) {
                      done = true;
                      canceled = true;
                  }
                  else if (value === breakLoop || (done && running <= 0)) {
                      done = true;
                      return callback(null);
                  }
                  else if (!looping) {
                      replenish();
                  }
              }
  
              function replenish () {
                  looping = true;
                  while (running < limit && !done) {
                      var elem = nextElem();
                      if (elem === null) {
                          done = true;
                          if (running <= 0) {
                              callback(null);
                          }
                          return;
                      }
                      running += 1;
                      iteratee(elem.value, elem.key, onlyOnce(iterateeCallback));
                  }
                  looping = false;
              }
  
              replenish();
          };
      };
  
      /**
       * The same as [`eachOf`]{@link module:Collections.eachOf} but runs a maximum of `limit` async operations at a
       * time.
       *
       * @name eachOfLimit
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.eachOf]{@link module:Collections.eachOf}
       * @alias forEachOfLimit
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {number} limit - The maximum number of async operations at a time.
       * @param {AsyncFunction} iteratee - An async function to apply to each
       * item in `coll`. The `key` is the item's key, or index in the case of an
       * array.
       * Invoked with (item, key, callback).
       * @param {Function} [callback] - A callback which is called when all
       * `iteratee` functions have finished, or an error occurs. Invoked with (err).
       * @returns {Promise} a promise, if a callback is omitted
       */
      function eachOfLimit$1(coll, limit, iteratee, callback) {
          return eachOfLimit(limit)(coll, wrapAsync(iteratee), callback);
      }
  
      var eachOfLimit$2 = awaitify(eachOfLimit$1, 4);
  
      // eachOf implementation optimized for array-likes
      function eachOfArrayLike(coll, iteratee, callback) {
          callback = once(callback);
          var index = 0,
              completed = 0,
              {length} = coll,
              canceled = false;
          if (length === 0) {
              callback(null);
          }
  
          function iteratorCallback(err, value) {
              if (err === false) {
                  canceled = true;
              }
              if (canceled === true) return
              if (err) {
                  callback(err);
              } else if ((++completed === length) || value === breakLoop) {
                  callback(null);
              }
          }
  
          for (; index < length; index++) {
              iteratee(coll[index], index, onlyOnce(iteratorCallback));
          }
      }
  
      // a generic version of eachOf which can handle array, object, and iterator cases.
      function eachOfGeneric (coll, iteratee, callback) {
          return eachOfLimit$2(coll, Infinity, iteratee, callback);
      }
  
      /**
       * Like [`each`]{@link module:Collections.each}, except that it passes the key (or index) as the second argument
       * to the iteratee.
       *
       * @name eachOf
       * @static
       * @memberOf module:Collections
       * @method
       * @alias forEachOf
       * @category Collection
       * @see [async.each]{@link module:Collections.each}
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - A function to apply to each
       * item in `coll`.
       * The `key` is the item's key, or index in the case of an array.
       * Invoked with (item, key, callback).
       * @param {Function} [callback] - A callback which is called when all
       * `iteratee` functions have finished, or an error occurs. Invoked with (err).
       * @returns {Promise} a promise, if a callback is omitted
       * @example
       *
       * var obj = {dev: "/dev.json", test: "/test.json", prod: "/prod.json"};
       * var configs = {};
       *
       * async.forEachOf(obj, function (value, key, callback) {
       *     fs.readFile(__dirname + value, "utf8", function (err, data) {
       *         if (err) return callback(err);
       *         try {
       *             configs[key] = JSON.parse(data);
       *         } catch (e) {
       *             return callback(e);
       *         }
       *         callback();
       *     });
       * }, function (err) {
       *     if (err) console.error(err.message);
       *     // configs is now a map of JSON data
       *     doSomethingWith(configs);
       * });
       */
      function eachOf(coll, iteratee, callback) {
          var eachOfImplementation = isArrayLike(coll) ? eachOfArrayLike : eachOfGeneric;
          return eachOfImplementation(coll, wrapAsync(iteratee), callback);
      }
  
      var eachOf$1 = awaitify(eachOf, 3);
  
      /**
       * Produces a new collection of values by mapping each value in `coll` through
       * the `iteratee` function. The `iteratee` is called with an item from `coll`
       * and a callback for when it has finished processing. Each of these callback
       * takes 2 arguments: an `error`, and the transformed item from `coll`. If
       * `iteratee` passes an error to its callback, the main `callback` (for the
       * `map` function) is immediately called with the error.
       *
       * Note, that since this function applies the `iteratee` to each item in
       * parallel, there is no guarantee that the `iteratee` functions will complete
       * in order. However, the results array will be in the same order as the
       * original `coll`.
       *
       * If `map` is passed an Object, the results will be an Array.  The results
       * will roughly be in the order of the original Objects' keys (but this can
       * vary across JavaScript engines).
       *
       * @name map
       * @static
       * @memberOf module:Collections
       * @method
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - An async function to apply to each item in
       * `coll`.
       * The iteratee should complete with the transformed item.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called when all `iteratee`
       * functions have finished, or an error occurs. Results is an Array of the
       * transformed items from the `coll`. Invoked with (err, results).
       * @returns {Promise} a promise, if no callback is passed
       * @example
       *
       * async.map(['file1','file2','file3'], fs.stat, function(err, results) {
       *     // results is now an array of stats for each file
       * });
       */
      function map (coll, iteratee, callback) {
          return _asyncMap(eachOf$1, coll, iteratee, callback)
      }
      var map$1 = awaitify(map, 3);
  
      /**
       * Applies the provided arguments to each function in the array, calling
       * `callback` after all functions have completed. If you only provide the first
       * argument, `fns`, then it will return a function which lets you pass in the
       * arguments as if it were a single function call. If more arguments are
       * provided, `callback` is required while `args` is still optional. The results
       * for each of the applied async functions are passed to the final callback
       * as an array.
       *
       * @name applyEach
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @category Control Flow
       * @param {Array|Iterable|AsyncIterable|Object} fns - A collection of {@link AsyncFunction}s
       * to all call with the same arguments
       * @param {...*} [args] - any number of separate arguments to pass to the
       * function.
       * @param {Function} [callback] - the final argument should be the callback,
       * called when all functions have completed processing.
       * @returns {Function} - If only the first argument, `fns`, is provided, it will
       * return a function which lets you pass in the arguments as if it were a single
       * function call. The signature is `(..args, callback)`. If invoked with any
       * arguments, `callback` is required.
       * @example
       *
       * async.applyEach([enableSearch, updateSchema], 'bucket', (err, results) => {
       *     // results[0] is the results for `enableSearch`
       *     // results[1] is the results for `updateSchema`
       * });
       *
       * // partial application example:
       * async.each(
       *     buckets,
       *     async.applyEach([enableSearch, updateSchema]),
       *     callback
       * );
       */
      var applyEach$1 = applyEach(map$1);
  
      /**
       * The same as [`eachOf`]{@link module:Collections.eachOf} but runs only a single async operation at a time.
       *
       * @name eachOfSeries
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.eachOf]{@link module:Collections.eachOf}
       * @alias forEachOfSeries
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - An async function to apply to each item in
       * `coll`.
       * Invoked with (item, key, callback).
       * @param {Function} [callback] - A callback which is called when all `iteratee`
       * functions have finished, or an error occurs. Invoked with (err).
       * @returns {Promise} a promise, if a callback is omitted
       */
      function eachOfSeries(coll, iteratee, callback) {
          return eachOfLimit$2(coll, 1, iteratee, callback)
      }
      var eachOfSeries$1 = awaitify(eachOfSeries, 3);
  
      /**
       * The same as [`map`]{@link module:Collections.map} but runs only a single async operation at a time.
       *
       * @name mapSeries
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.map]{@link module:Collections.map}
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - An async function to apply to each item in
       * `coll`.
       * The iteratee should complete with the transformed item.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called when all `iteratee`
       * functions have finished, or an error occurs. Results is an array of the
       * transformed items from the `coll`. Invoked with (err, results).
       * @returns {Promise} a promise, if no callback is passed
       */
      function mapSeries (coll, iteratee, callback) {
          return _asyncMap(eachOfSeries$1, coll, iteratee, callback)
      }
      var mapSeries$1 = awaitify(mapSeries, 3);
  
      /**
       * The same as [`applyEach`]{@link module:ControlFlow.applyEach} but runs only a single async operation at a time.
       *
       * @name applyEachSeries
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @see [async.applyEach]{@link module:ControlFlow.applyEach}
       * @category Control Flow
       * @param {Array|Iterable|AsyncIterable|Object} fns - A collection of {@link AsyncFunction}s to all
       * call with the same arguments
       * @param {...*} [args] - any number of separate arguments to pass to the
       * function.
       * @param {Function} [callback] - the final argument should be the callback,
       * called when all functions have completed processing.
       * @returns {Function} - If only the first argument is provided, it will return
       * a function which lets you pass in the arguments as if it were a single
       * function call.
       */
      var applyEachSeries = applyEach(mapSeries$1);
  
      const PROMISE_SYMBOL = Symbol('promiseCallback');
  
      function promiseCallback () {
          let resolve, reject;
          function callback (err, ...args) {
              if (err) return reject(err)
              resolve(args.length > 1 ? args : args[0]);
          }
  
          callback[PROMISE_SYMBOL] = new Promise((res, rej) => {
              resolve = res,
              reject = rej;
          });
  
          return callback
      }
  
      /**
       * Determines the best order for running the {@link AsyncFunction}s in `tasks`, based on
       * their requirements. Each function can optionally depend on other functions
       * being completed first, and each function is run as soon as its requirements
       * are satisfied.
       *
       * If any of the {@link AsyncFunction}s pass an error to their callback, the `auto` sequence
       * will stop. Further tasks will not execute (so any other functions depending
       * on it will not run), and the main `callback` is immediately called with the
       * error.
       *
       * {@link AsyncFunction}s also receive an object containing the results of functions which
       * have completed so far as the first argument, if they have dependencies. If a
       * task function has no dependencies, it will only be passed a callback.
       *
       * @name auto
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @category Control Flow
       * @param {Object} tasks - An object. Each of its properties is either a
       * function or an array of requirements, with the {@link AsyncFunction} itself the last item
       * in the array. The object's key of a property serves as the name of the task
       * defined by that property, i.e. can be used when specifying requirements for
       * other tasks. The function receives one or two arguments:
       * * a `results` object, containing the results of the previously executed
       *   functions, only passed if the task has any dependencies,
       * * a `callback(err, result)` function, which must be called when finished,
       *   passing an `error` (which can be `null`) and the result of the function's
       *   execution.
       * @param {number} [concurrency=Infinity] - An optional `integer` for
       * determining the maximum number of tasks that can be run in parallel. By
       * default, as many as possible.
       * @param {Function} [callback] - An optional callback which is called when all
       * the tasks have been completed. It receives the `err` argument if any `tasks`
       * pass an error to their callback. Results are always returned; however, if an
       * error occurs, no further `tasks` will be performed, and the results object
       * will only contain partial results. Invoked with (err, results).
       * @returns {Promise} a promise, if a callback is not passed
       * @example
       *
       * async.auto({
       *     // this function will just be passed a callback
       *     readData: async.apply(fs.readFile, 'data.txt', 'utf-8'),
       *     showData: ['readData', function(results, cb) {
       *         // results.readData is the file's contents
       *         // ...
       *     }]
       * }, callback);
       *
       * async.auto({
       *     get_data: function(callback) {
       *         console.log('in get_data');
       *         // async code to get some data
       *         callback(null, 'data', 'converted to array');
       *     },
       *     make_folder: function(callback) {
       *         console.log('in make_folder');
       *         // async code to create a directory to store a file in
       *         // this is run at the same time as getting the data
       *         callback(null, 'folder');
       *     },
       *     write_file: ['get_data', 'make_folder', function(results, callback) {
       *         console.log('in write_file', JSON.stringify(results));
       *         // once there is some data and the directory exists,
       *         // write the data to a file in the directory
       *         callback(null, 'filename');
       *     }],
       *     email_link: ['write_file', function(results, callback) {
       *         console.log('in email_link', JSON.stringify(results));
       *         // once the file is written let's email a link to it...
       *         // results.write_file contains the filename returned by write_file.
       *         callback(null, {'file':results.write_file, 'email':'user@example.com'});
       *     }]
       * }, function(err, results) {
       *     console.log('err = ', err);
       *     console.log('results = ', results);
       * });
       */
      function auto(tasks, concurrency, callback) {
          if (typeof concurrency !== 'number') {
              // concurrency is optional, shift the args.
              callback = concurrency;
              concurrency = null;
          }
          callback = once(callback || promiseCallback());
          var numTasks = Object.keys(tasks).length;
          if (!numTasks) {
              return callback(null);
          }
          if (!concurrency) {
              concurrency = numTasks;
          }
  
          var results = {};
          var runningTasks = 0;
          var canceled = false;
          var hasError = false;
  
          var listeners = Object.create(null);
  
          var readyTasks = [];
  
          // for cycle detection:
          var readyToCheck = []; // tasks that have been identified as reachable
          // without the possibility of returning to an ancestor task
          var uncheckedDependencies = {};
  
          Object.keys(tasks).forEach(key => {
              var task = tasks[key];
              if (!Array.isArray(task)) {
                  // no dependencies
                  enqueueTask(key, [task]);
                  readyToCheck.push(key);
                  return;
              }
  
              var dependencies = task.slice(0, task.length - 1);
              var remainingDependencies = dependencies.length;
              if (remainingDependencies === 0) {
                  enqueueTask(key, task);
                  readyToCheck.push(key);
                  return;
              }
              uncheckedDependencies[key] = remainingDependencies;
  
              dependencies.forEach(dependencyName => {
                  if (!tasks[dependencyName]) {
                      throw new Error('async.auto task `' + key +
                          '` has a non-existent dependency `' +
                          dependencyName + '` in ' +
                          dependencies.join(', '));
                  }
                  addListener(dependencyName, () => {
                      remainingDependencies--;
                      if (remainingDependencies === 0) {
                          enqueueTask(key, task);
                      }
                  });
              });
          });
  
          checkForDeadlocks();
          processQueue();
  
          function enqueueTask(key, task) {
              readyTasks.push(() => runTask(key, task));
          }
  
          function processQueue() {
              if (canceled) return
              if (readyTasks.length === 0 && runningTasks === 0) {
                  return callback(null, results);
              }
              while(readyTasks.length && runningTasks < concurrency) {
                  var run = readyTasks.shift();
                  run();
              }
  
          }
  
          function addListener(taskName, fn) {
              var taskListeners = listeners[taskName];
              if (!taskListeners) {
                  taskListeners = listeners[taskName] = [];
              }
  
              taskListeners.push(fn);
          }
  
          function taskComplete(taskName) {
              var taskListeners = listeners[taskName] || [];
              taskListeners.forEach(fn => fn());
              processQueue();
          }
  
  
          function runTask(key, task) {
              if (hasError) return;
  
              var taskCallback = onlyOnce((err, ...result) => {
                  runningTasks--;
                  if (err === false) {
                      canceled = true;
                      return
                  }
                  if (result.length < 2) {
                      [result] = result;
                  }
                  if (err) {
                      var safeResults = {};
                      Object.keys(results).forEach(rkey => {
                          safeResults[rkey] = results[rkey];
                      });
                      safeResults[key] = result;
                      hasError = true;
                      listeners = Object.create(null);
                      if (canceled) return
                      callback(err, safeResults);
                  } else {
                      results[key] = result;
                      taskComplete(key);
                  }
              });
  
              runningTasks++;
              var taskFn = wrapAsync(task[task.length - 1]);
              if (task.length > 1) {
                  taskFn(results, taskCallback);
              } else {
                  taskFn(taskCallback);
              }
          }
  
          function checkForDeadlocks() {
              // Kahn's algorithm
              // https://en.wikipedia.org/wiki/Topological_sorting#Kahn.27s_algorithm
              // http://connalle.blogspot.com/2013/10/topological-sortingkahn-algorithm.html
              var currentTask;
              var counter = 0;
              while (readyToCheck.length) {
                  currentTask = readyToCheck.pop();
                  counter++;
                  getDependents(currentTask).forEach(dependent => {
                      if (--uncheckedDependencies[dependent] === 0) {
                          readyToCheck.push(dependent);
                      }
                  });
              }
  
              if (counter !== numTasks) {
                  throw new Error(
                      'async.auto cannot execute tasks due to a recursive dependency'
                  );
              }
          }
  
          function getDependents(taskName) {
              var result = [];
              Object.keys(tasks).forEach(key => {
                  const task = tasks[key];
                  if (Array.isArray(task) && task.indexOf(taskName) >= 0) {
                      result.push(key);
                  }
              });
              return result;
          }
  
          return callback[PROMISE_SYMBOL]
      }
  
      var FN_ARGS = /^(?:async\s+)?(?:function)?\s*[^(]*\(\s*([^)]+)\s*\)(?:\s*{)/m;
      var ARROW_FN_ARGS = /^(?:async\s+)?(?:function\s+)?\(?\s*([^)^=]+)\s*\)?(?:\s*=>)/m;
      var FN_ARG_SPLIT = /,/;
      var FN_ARG = /(=.+)?(\s*)$/;
      var STRIP_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg;
  
      function parseParams(func) {
          const src = func.toString().replace(STRIP_COMMENTS, '');
          let match = src.match(FN_ARGS);
          if (!match) {
              match = src.match(ARROW_FN_ARGS);
          }
          if (!match) throw new Error('could not parse args in autoInject\nSource:\n' + src)
          let [, args] = match;
          return args
              .replace(/\s/g, '')
              .split(FN_ARG_SPLIT)
              .map((arg) => arg.replace(FN_ARG, '').trim());
      }
  
      /**
       * A dependency-injected version of the [async.auto]{@link module:ControlFlow.auto} function. Dependent
       * tasks are specified as parameters to the function, after the usual callback
       * parameter, with the parameter names matching the names of the tasks it
       * depends on. This can provide even more readable task graphs which can be
       * easier to maintain.
       *
       * If a final callback is specified, the task results are similarly injected,
       * specified as named parameters after the initial error parameter.
       *
       * The autoInject function is purely syntactic sugar and its semantics are
       * otherwise equivalent to [async.auto]{@link module:ControlFlow.auto}.
       *
       * @name autoInject
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @see [async.auto]{@link module:ControlFlow.auto}
       * @category Control Flow
       * @param {Object} tasks - An object, each of whose properties is an {@link AsyncFunction} of
       * the form 'func([dependencies...], callback). The object's key of a property
       * serves as the name of the task defined by that property, i.e. can be used
       * when specifying requirements for other tasks.
       * * The `callback` parameter is a `callback(err, result)` which must be called
       *   when finished, passing an `error` (which can be `null`) and the result of
       *   the function's execution. The remaining parameters name other tasks on
       *   which the task is dependent, and the results from those tasks are the
       *   arguments of those parameters.
       * @param {Function} [callback] - An optional callback which is called when all
       * the tasks have been completed. It receives the `err` argument if any `tasks`
       * pass an error to their callback, and a `results` object with any completed
       * task results, similar to `auto`.
       * @returns {Promise} a promise, if no callback is passed
       * @example
       *
       * //  The example from `auto` can be rewritten as follows:
       * async.autoInject({
       *     get_data: function(callback) {
       *         // async code to get some data
       *         callback(null, 'data', 'converted to array');
       *     },
       *     make_folder: function(callback) {
       *         // async code to create a directory to store a file in
       *         // this is run at the same time as getting the data
       *         callback(null, 'folder');
       *     },
       *     write_file: function(get_data, make_folder, callback) {
       *         // once there is some data and the directory exists,
       *         // write the data to a file in the directory
       *         callback(null, 'filename');
       *     },
       *     email_link: function(write_file, callback) {
       *         // once the file is written let's email a link to it...
       *         // write_file contains the filename returned by write_file.
       *         callback(null, {'file':write_file, 'email':'user@example.com'});
       *     }
       * }, function(err, results) {
       *     console.log('err = ', err);
       *     console.log('email_link = ', results.email_link);
       * });
       *
       * // If you are using a JS minifier that mangles parameter names, `autoInject`
       * // will not work with plain functions, since the parameter names will be
       * // collapsed to a single letter identifier.  To work around this, you can
       * // explicitly specify the names of the parameters your task function needs
       * // in an array, similar to Angular.js dependency injection.
       *
       * // This still has an advantage over plain `auto`, since the results a task
       * // depends on are still spread into arguments.
       * async.autoInject({
       *     //...
       *     write_file: ['get_data', 'make_folder', function(get_data, make_folder, callback) {
       *         callback(null, 'filename');
       *     }],
       *     email_link: ['write_file', function(write_file, callback) {
       *         callback(null, {'file':write_file, 'email':'user@example.com'});
       *     }]
       *     //...
       * }, function(err, results) {
       *     console.log('err = ', err);
       *     console.log('email_link = ', results.email_link);
       * });
       */
      function autoInject(tasks, callback) {
          var newTasks = {};
  
          Object.keys(tasks).forEach(key => {
              var taskFn = tasks[key];
              var params;
              var fnIsAsync = isAsync(taskFn);
              var hasNoDeps =
                  (!fnIsAsync && taskFn.length === 1) ||
                  (fnIsAsync && taskFn.length === 0);
  
              if (Array.isArray(taskFn)) {
                  params = [...taskFn];
                  taskFn = params.pop();
  
                  newTasks[key] = params.concat(params.length > 0 ? newTask : taskFn);
              } else if (hasNoDeps) {
                  // no dependencies, use the function as-is
                  newTasks[key] = taskFn;
              } else {
                  params = parseParams(taskFn);
                  if ((taskFn.length === 0 && !fnIsAsync) && params.length === 0) {
                      throw new Error("autoInject task functions require explicit parameters.");
                  }
  
                  // remove callback param
                  if (!fnIsAsync) params.pop();
  
                  newTasks[key] = params.concat(newTask);
              }
  
              function newTask(results, taskCb) {
                  var newArgs = params.map(name => results[name]);
                  newArgs.push(taskCb);
                  wrapAsync(taskFn)(...newArgs);
              }
          });
  
          return auto(newTasks, callback);
      }
  
      // Simple doubly linked list (https://en.wikipedia.org/wiki/Doubly_linked_list) implementation
      // used for queues. This implementation assumes that the node provided by the user can be modified
      // to adjust the next and last properties. We implement only the minimal functionality
      // for queue support.
      class DLL {
          constructor() {
              this.head = this.tail = null;
              this.length = 0;
          }
  
          removeLink(node) {
              if (node.prev) node.prev.next = node.next;
              else this.head = node.next;
              if (node.next) node.next.prev = node.prev;
              else this.tail = node.prev;
  
              node.prev = node.next = null;
              this.length -= 1;
              return node;
          }
  
          empty () {
              while(this.head) this.shift();
              return this;
          }
  
          insertAfter(node, newNode) {
              newNode.prev = node;
              newNode.next = node.next;
              if (node.next) node.next.prev = newNode;
              else this.tail = newNode;
              node.next = newNode;
              this.length += 1;
          }
  
          insertBefore(node, newNode) {
              newNode.prev = node.prev;
              newNode.next = node;
              if (node.prev) node.prev.next = newNode;
              else this.head = newNode;
              node.prev = newNode;
              this.length += 1;
          }
  
          unshift(node) {
              if (this.head) this.insertBefore(this.head, node);
              else setInitial(this, node);
          }
  
          push(node) {
              if (this.tail) this.insertAfter(this.tail, node);
              else setInitial(this, node);
          }
  
          shift() {
              return this.head && this.removeLink(this.head);
          }
  
          pop() {
              return this.tail && this.removeLink(this.tail);
          }
  
          toArray() {
              return [...this]
          }
  
          *[Symbol.iterator] () {
              var cur = this.head;
              while (cur) {
                  yield cur.data;
                  cur = cur.next;
              }
          }
  
          remove (testFn) {
              var curr = this.head;
              while(curr) {
                  var {next} = curr;
                  if (testFn(curr)) {
                      this.removeLink(curr);
                  }
                  curr = next;
              }
              return this;
          }
      }
  
      function setInitial(dll, node) {
          dll.length = 1;
          dll.head = dll.tail = node;
      }
  
      function queue(worker, concurrency, payload) {
          if (concurrency == null) {
              concurrency = 1;
          }
          else if(concurrency === 0) {
              throw new RangeError('Concurrency must not be zero');
          }
  
          var _worker = wrapAsync(worker);
          var numRunning = 0;
          var workersList = [];
          const events = {
              error: [],
              drain: [],
              saturated: [],
              unsaturated: [],
              empty: []
          };
  
          function on (event, handler) {
              events[event].push(handler);
          }
  
          function once (event, handler) {
              const handleAndRemove = (...args) => {
                  off(event, handleAndRemove);
                  handler(...args);
              };
              events[event].push(handleAndRemove);
          }
  
          function off (event, handler) {
              if (!event) return Object.keys(events).forEach(ev => events[ev] = [])
              if (!handler) return events[event] = []
              events[event] = events[event].filter(ev => ev !== handler);
          }
  
          function trigger (event, ...args) {
              events[event].forEach(handler => handler(...args));
          }
  
          var processingScheduled = false;
          function _insert(data, insertAtFront, callback) {
              if (callback != null && typeof callback !== 'function') {
                  throw new Error('task callback must be a function');
              }
              q.started = true;
              if (Array.isArray(data)) {
                  if (data.length === 0 && q.idle()) {
                      // call drain immediately if there are no tasks
                      return setImmediate$1(() => trigger('drain'));
                  }
  
                  return data.map(datum => _insert(datum, insertAtFront, callback));
              }
  
              var res;
  
              var item = {
                  data,
                  callback: callback || function (err, ...args) {
                      // we don't care about the error, let the global error handler
                      // deal with it
                      if (err) return
                      if (args.length <= 1) return res(args[0])
                      res(args);
                  }
              };
  
              if (insertAtFront) {
                  q._tasks.unshift(item);
              } else {
                  q._tasks.push(item);
              }
  
              if (!processingScheduled) {
                  processingScheduled = true;
                  setImmediate$1(() => {
                      processingScheduled = false;
                      q.process();
                  });
              }
  
              if (!callback) {
                  return new Promise((resolve) => {
                      res = resolve;
                  })
              }
          }
  
          function _createCB(tasks) {
              return function (err, ...args) {
                  numRunning -= 1;
  
                  for (var i = 0, l = tasks.length; i < l; i++) {
                      var task = tasks[i];
  
                      var index = workersList.indexOf(task);
                      if (index === 0) {
                          workersList.shift();
                      } else if (index > 0) {
                          workersList.splice(index, 1);
                      }
  
                      task.callback(err, ...args);
  
                      if (err != null) {
                          trigger('error', err, task.data);
                      }
                  }
  
                  if (numRunning <= (q.concurrency - q.buffer) ) {
                      trigger('unsaturated');
                  }
  
                  if (q.idle()) {
                      trigger('drain');
                  }
                  q.process();
              };
          }
  
          const eventMethod = (name) => (handler) => {
              if (!handler) {
                  return new Promise((resolve, reject) => {
                      once(name, (err, data) => {
                          if (err) return reject(err)
                          resolve(data);
                      });
                  })
              }
              off(name);
              on(name, handler);
  
          };
  
          var isProcessing = false;
          var q = {
              _tasks: new DLL(),
              *[Symbol.iterator] () {
                  yield* q._tasks[Symbol.iterator]();
              },
              concurrency,
              payload,
              buffer: concurrency / 4,
              started: false,
              paused: false,
              push (data, callback) {
                  return _insert(data, false, callback);
              },
              kill () {
                  off();
                  q._tasks.empty();
              },
              unshift (data, callback) {
                  return _insert(data, true, callback);
              },
              remove (testFn) {
                  q._tasks.remove(testFn);
              },
              process () {
                  // Avoid trying to start too many processing operations. This can occur
                  // when callbacks resolve synchronously (#1267).
                  if (isProcessing) {
                      return;
                  }
                  isProcessing = true;
                  while(!q.paused && numRunning < q.concurrency && q._tasks.length){
                      var tasks = [], data = [];
                      var l = q._tasks.length;
                      if (q.payload) l = Math.min(l, q.payload);
                      for (var i = 0; i < l; i++) {
                          var node = q._tasks.shift();
                          tasks.push(node);
                          workersList.push(node);
                          data.push(node.data);
                      }
  
                      numRunning += 1;
  
                      if (q._tasks.length === 0) {
                          trigger('empty');
                      }
  
                      if (numRunning === q.concurrency) {
                          trigger('saturated');
                      }
  
                      var cb = onlyOnce(_createCB(tasks));
                      _worker(data, cb);
                  }
                  isProcessing = false;
              },
              length () {
                  return q._tasks.length;
              },
              running () {
                  return numRunning;
              },
              workersList () {
                  return workersList;
              },
              idle() {
                  return q._tasks.length + numRunning === 0;
              },
              pause () {
                  q.paused = true;
              },
              resume () {
                  if (q.paused === false) { return; }
                  q.paused = false;
                  setImmediate$1(q.process);
              }
          };
          // define these as fixed properties, so people get useful errors when updating
          Object.defineProperties(q, {
              saturated: {
                  writable: false,
                  value: eventMethod('saturated')
              },
              unsaturated: {
                  writable: false,
                  value: eventMethod('unsaturated')
              },
              empty: {
                  writable: false,
                  value: eventMethod('empty')
              },
              drain: {
                  writable: false,
                  value: eventMethod('drain')
              },
              error: {
                  writable: false,
                  value: eventMethod('error')
              },
          });
          return q;
      }
  
      /**
       * Creates a `cargo` object with the specified payload. Tasks added to the
       * cargo will be processed altogether (up to the `payload` limit). If the
       * `worker` is in progress, the task is queued until it becomes available. Once
       * the `worker` has completed some tasks, each callback of those tasks is
       * called. Check out [these](https://camo.githubusercontent.com/6bbd36f4cf5b35a0f11a96dcd2e97711ffc2fb37/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f313637363837312f36383130382f62626330636662302d356632392d313165322d393734662d3333393763363464633835382e676966) [animations](https://camo.githubusercontent.com/f4810e00e1c5f5f8addbe3e9f49064fd5d102699/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f313637363837312f36383130312f38346339323036362d356632392d313165322d383134662d3964336430323431336266642e676966)
       * for how `cargo` and `queue` work.
       *
       * While [`queue`]{@link module:ControlFlow.queue} passes only one task to one of a group of workers
       * at a time, cargo passes an array of tasks to a single worker, repeating
       * when the worker is finished.
       *
       * @name cargo
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @see [async.queue]{@link module:ControlFlow.queue}
       * @category Control Flow
       * @param {AsyncFunction} worker - An asynchronous function for processing an array
       * of queued tasks. Invoked with `(tasks, callback)`.
       * @param {number} [payload=Infinity] - An optional `integer` for determining
       * how many tasks should be processed per round; if omitted, the default is
       * unlimited.
       * @returns {module:ControlFlow.QueueObject} A cargo object to manage the tasks. Callbacks can
       * attached as certain properties to listen for specific events during the
       * lifecycle of the cargo and inner queue.
       * @example
       *
       * // create a cargo object with payload 2
       * var cargo = async.cargo(function(tasks, callback) {
       *     for (var i=0; i<tasks.length; i++) {
       *         console.log('hello ' + tasks[i].name);
       *     }
       *     callback();
       * }, 2);
       *
       * // add some items
       * cargo.push({name: 'foo'}, function(err) {
       *     console.log('finished processing foo');
       * });
       * cargo.push({name: 'bar'}, function(err) {
       *     console.log('finished processing bar');
       * });
       * await cargo.push({name: 'baz'});
       * console.log('finished processing baz');
       */
      function cargo(worker, payload) {
          return queue(worker, 1, payload);
      }
  
      /**
       * Creates a `cargoQueue` object with the specified payload. Tasks added to the
       * cargoQueue will be processed together (up to the `payload` limit) in `concurrency` parallel workers.
       * If the all `workers` are in progress, the task is queued until one becomes available. Once
       * a `worker` has completed some tasks, each callback of those tasks is
       * called. Check out [these](https://camo.githubusercontent.com/6bbd36f4cf5b35a0f11a96dcd2e97711ffc2fb37/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f313637363837312f36383130382f62626330636662302d356632392d313165322d393734662d3333393763363464633835382e676966) [animations](https://camo.githubusercontent.com/f4810e00e1c5f5f8addbe3e9f49064fd5d102699/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f313637363837312f36383130312f38346339323036362d356632392d313165322d383134662d3964336430323431336266642e676966)
       * for how `cargo` and `queue` work.
       *
       * While [`queue`]{@link module:ControlFlow.queue} passes only one task to one of a group of workers
       * at a time, and [`cargo`]{@link module:ControlFlow.cargo} passes an array of tasks to a single worker,
       * the cargoQueue passes an array of tasks to multiple parallel workers.
       *
       * @name cargoQueue
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @see [async.queue]{@link module:ControlFlow.queue}
       * @see [async.cargo]{@link module:ControlFLow.cargo}
       * @category Control Flow
       * @param {AsyncFunction} worker - An asynchronous function for processing an array
       * of queued tasks. Invoked with `(tasks, callback)`.
       * @param {number} [concurrency=1] - An `integer` for determining how many
       * `worker` functions should be run in parallel.  If omitted, the concurrency
       * defaults to `1`.  If the concurrency is `0`, an error is thrown.
       * @param {number} [payload=Infinity] - An optional `integer` for determining
       * how many tasks should be processed per round; if omitted, the default is
       * unlimited.
       * @returns {module:ControlFlow.CargoObject} A cargoQueue object to manage the tasks. Callbacks can
       * attached as certain properties to listen for specific events during the
       * lifecycle of the cargoQueue and inner queue.
       * @example
       *
       * // create a cargoQueue object with payload 2 and concurrency 2
       * var cargoQueue = async.cargoQueue(function(tasks, callback) {
       *     for (var i=0; i<tasks.length; i++) {
       *         console.log('hello ' + tasks[i].name);
       *     }
       *     callback();
       * }, 2, 2);
       *
       * // add some items
       * cargoQueue.push({name: 'foo'}, function(err) {
       *     console.log('finished processing foo');
       * });
       * cargoQueue.push({name: 'bar'}, function(err) {
       *     console.log('finished processing bar');
       * });
       * cargoQueue.push({name: 'baz'}, function(err) {
       *     console.log('finished processing baz');
       * });
       * cargoQueue.push({name: 'boo'}, function(err) {
       *     console.log('finished processing boo');
       * });
       */
      function cargo$1(worker, concurrency, payload) {
          return queue(worker, concurrency, payload);
      }
  
      /**
       * Reduces `coll` into a single value using an async `iteratee` to return each
       * successive step. `memo` is the initial state of the reduction. This function
       * only operates in series.
       *
       * For performance reasons, it may make sense to split a call to this function
       * into a parallel map, and then use the normal `Array.prototype.reduce` on the
       * results. This function is for situations where each step in the reduction
       * needs to be async; if you can get the data before reducing it, then it's
       * probably a good idea to do so.
       *
       * @name reduce
       * @static
       * @memberOf module:Collections
       * @method
       * @alias inject
       * @alias foldl
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {*} memo - The initial state of the reduction.
       * @param {AsyncFunction} iteratee - A function applied to each item in the
       * array to produce the next step in the reduction.
       * The `iteratee` should complete with the next state of the reduction.
       * If the iteratee complete with an error, the reduction is stopped and the
       * main `callback` is immediately called with the error.
       * Invoked with (memo, item, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished. Result is the reduced value. Invoked with
       * (err, result).
       * @returns {Promise} a promise, if no callback is passed
       * @example
       *
       * async.reduce([1,2,3], 0, function(memo, item, callback) {
       *     // pointless async:
       *     process.nextTick(function() {
       *         callback(null, memo + item)
       *     });
       * }, function(err, result) {
       *     // result is now equal to the last value of memo, which is 6
       * });
       */
      function reduce(coll, memo, iteratee, callback) {
          callback = once(callback);
          var _iteratee = wrapAsync(iteratee);
          return eachOfSeries$1(coll, (x, i, iterCb) => {
              _iteratee(memo, x, (err, v) => {
                  memo = v;
                  iterCb(err);
              });
          }, err => callback(err, memo));
      }
      var reduce$1 = awaitify(reduce, 4);
  
      /**
       * Version of the compose function that is more natural to read. Each function
       * consumes the return value of the previous function. It is the equivalent of
       * [compose]{@link module:ControlFlow.compose} with the arguments reversed.
       *
       * Each function is executed with the `this` binding of the composed function.
       *
       * @name seq
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @see [async.compose]{@link module:ControlFlow.compose}
       * @category Control Flow
       * @param {...AsyncFunction} functions - the asynchronous functions to compose
       * @returns {Function} a function that composes the `functions` in order
       * @example
       *
       * // Requires lodash (or underscore), express3 and dresende's orm2.
       * // Part of an app, that fetches cats of the logged user.
       * // This example uses `seq` function to avoid overnesting and error
       * // handling clutter.
       * app.get('/cats', function(request, response) {
       *     var User = request.models.User;
       *     async.seq(
       *         _.bind(User.get, User),  // 'User.get' has signature (id, callback(err, data))
       *         function(user, fn) {
       *             user.getCats(fn);      // 'getCats' has signature (callback(err, data))
       *         }
       *     )(req.session.user_id, function (err, cats) {
       *         if (err) {
       *             console.error(err);
       *             response.json({ status: 'error', message: err.message });
       *         } else {
       *             response.json({ status: 'ok', message: 'Cats found', data: cats });
       *         }
       *     });
       * });
       */
      function seq(...functions) {
          var _functions = functions.map(wrapAsync);
          return function (...args) {
              var that = this;
  
              var cb = args[args.length - 1];
              if (typeof cb == 'function') {
                  args.pop();
              } else {
                  cb = promiseCallback();
              }
  
              reduce$1(_functions, args, (newargs, fn, iterCb) => {
                  fn.apply(that, newargs.concat((err, ...nextargs) => {
                      iterCb(err, nextargs);
                  }));
              },
              (err, results) => cb(err, ...results));
  
              return cb[PROMISE_SYMBOL]
          };
      }
  
      /**
       * Creates a function which is a composition of the passed asynchronous
       * functions. Each function consumes the return value of the function that
       * follows. Composing functions `f()`, `g()`, and `h()` would produce the result
       * of `f(g(h()))`, only this version uses callbacks to obtain the return values.
       *
       * If the last argument to the composed function is not a function, a promise
       * is returned when you call it.
       *
       * Each function is executed with the `this` binding of the composed function.
       *
       * @name compose
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @category Control Flow
       * @param {...AsyncFunction} functions - the asynchronous functions to compose
       * @returns {Function} an asynchronous function that is the composed
       * asynchronous `functions`
       * @example
       *
       * function add1(n, callback) {
       *     setTimeout(function () {
       *         callback(null, n + 1);
       *     }, 10);
       * }
       *
       * function mul3(n, callback) {
       *     setTimeout(function () {
       *         callback(null, n * 3);
       *     }, 10);
       * }
       *
       * var add1mul3 = async.compose(mul3, add1);
       * add1mul3(4, function (err, result) {
       *     // result now equals 15
       * });
       */
      function compose(...args) {
          return seq(...args.reverse());
      }
  
      /**
       * The same as [`map`]{@link module:Collections.map} but runs a maximum of `limit` async operations at a time.
       *
       * @name mapLimit
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.map]{@link module:Collections.map}
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {number} limit - The maximum number of async operations at a time.
       * @param {AsyncFunction} iteratee - An async function to apply to each item in
       * `coll`.
       * The iteratee should complete with the transformed item.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called when all `iteratee`
       * functions have finished, or an error occurs. Results is an array of the
       * transformed items from the `coll`. Invoked with (err, results).
       * @returns {Promise} a promise, if no callback is passed
       */
      function mapLimit (coll, limit, iteratee, callback) {
          return _asyncMap(eachOfLimit(limit), coll, iteratee, callback)
      }
      var mapLimit$1 = awaitify(mapLimit, 4);
  
      /**
       * The same as [`concat`]{@link module:Collections.concat} but runs a maximum of `limit` async operations at a time.
       *
       * @name concatLimit
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.concat]{@link module:Collections.concat}
       * @category Collection
       * @alias flatMapLimit
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {number} limit - The maximum number of async operations at a time.
       * @param {AsyncFunction} iteratee - A function to apply to each item in `coll`,
       * which should use an array as its result. Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished, or an error occurs. Results is an array
       * containing the concatenated results of the `iteratee` function. Invoked with
       * (err, results).
       * @returns A Promise, if no callback is passed
       */
      function concatLimit(coll, limit, iteratee, callback) {
          var _iteratee = wrapAsync(iteratee);
          return mapLimit$1(coll, limit, (val, iterCb) => {
              _iteratee(val, (err, ...args) => {
                  if (err) return iterCb(err);
                  return iterCb(err, args);
              });
          }, (err, mapResults) => {
              var result = [];
              for (var i = 0; i < mapResults.length; i++) {
                  if (mapResults[i]) {
                      result = result.concat(...mapResults[i]);
                  }
              }
  
              return callback(err, result);
          });
      }
      var concatLimit$1 = awaitify(concatLimit, 4);
  
      /**
       * Applies `iteratee` to each item in `coll`, concatenating the results. Returns
       * the concatenated list. The `iteratee`s are called in parallel, and the
       * results are concatenated as they return. The results array will be returned in
       * the original order of `coll` passed to the `iteratee` function.
       *
       * @name concat
       * @static
       * @memberOf module:Collections
       * @method
       * @category Collection
       * @alias flatMap
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - A function to apply to each item in `coll`,
       * which should use an array as its result. Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished, or an error occurs. Results is an array
       * containing the concatenated results of the `iteratee` function. Invoked with
       * (err, results).
       * @returns A Promise, if no callback is passed
       * @example
       *
       * async.concat(['dir1','dir2','dir3'], fs.readdir, function(err, files) {
       *     // files is now a list of filenames that exist in the 3 directories
       * });
       */
      function concat(coll, iteratee, callback) {
          return concatLimit$1(coll, Infinity, iteratee, callback)
      }
      var concat$1 = awaitify(concat, 3);
  
      /**
       * The same as [`concat`]{@link module:Collections.concat} but runs only a single async operation at a time.
       *
       * @name concatSeries
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.concat]{@link module:Collections.concat}
       * @category Collection
       * @alias flatMapSeries
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - A function to apply to each item in `coll`.
       * The iteratee should complete with an array an array of results.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished, or an error occurs. Results is an array
       * containing the concatenated results of the `iteratee` function. Invoked with
       * (err, results).
       * @returns A Promise, if no callback is passed
       */
      function concatSeries(coll, iteratee, callback) {
          return concatLimit$1(coll, 1, iteratee, callback)
      }
      var concatSeries$1 = awaitify(concatSeries, 3);
  
      /**
       * Returns a function that when called, calls-back with the values provided.
       * Useful as the first function in a [`waterfall`]{@link module:ControlFlow.waterfall}, or for plugging values in to
       * [`auto`]{@link module:ControlFlow.auto}.
       *
       * @name constant
       * @static
       * @memberOf module:Utils
       * @method
       * @category Util
       * @param {...*} arguments... - Any number of arguments to automatically invoke
       * callback with.
       * @returns {AsyncFunction} Returns a function that when invoked, automatically
       * invokes the callback with the previous given arguments.
       * @example
       *
       * async.waterfall([
       *     async.constant(42),
       *     function (value, next) {
       *         // value === 42
       *     },
       *     //...
       * ], callback);
       *
       * async.waterfall([
       *     async.constant(filename, "utf8"),
       *     fs.readFile,
       *     function (fileData, next) {
       *         //...
       *     }
       *     //...
       * ], callback);
       *
       * async.auto({
       *     hostname: async.constant("https://server.net/"),
       *     port: findFreePort,
       *     launchServer: ["hostname", "port", function (options, cb) {
       *         startServer(options, cb);
       *     }],
       *     //...
       * }, callback);
       */
      function constant(...args) {
          return function (...ignoredArgs/*, callback*/) {
              var callback = ignoredArgs.pop();
              return callback(null, ...args);
          };
      }
  
      function _createTester(check, getResult) {
          return (eachfn, arr, _iteratee, cb) => {
              var testPassed = false;
              var testResult;
              const iteratee = wrapAsync(_iteratee);
              eachfn(arr, (value, _, callback) => {
                  iteratee(value, (err, result) => {
                      if (err || err === false) return callback(err);
  
                      if (check(result) && !testResult) {
                          testPassed = true;
                          testResult = getResult(true, value);
                          return callback(null, breakLoop);
                      }
                      callback();
                  });
              }, err => {
                  if (err) return cb(err);
                  cb(null, testPassed ? testResult : getResult(false));
              });
          };
      }
  
      /**
       * Returns the first value in `coll` that passes an async truth test. The
       * `iteratee` is applied in parallel, meaning the first iteratee to return
       * `true` will fire the detect `callback` with that result. That means the
       * result might not be the first item in the original `coll` (in terms of order)
       * that passes the test.
  
       * If order within the original `coll` is important, then look at
       * [`detectSeries`]{@link module:Collections.detectSeries}.
       *
       * @name detect
       * @static
       * @memberOf module:Collections
       * @method
       * @alias find
       * @category Collections
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - A truth test to apply to each item in `coll`.
       * The iteratee must complete with a boolean value as its result.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called as soon as any
       * iteratee returns `true`, or after all the `iteratee` functions have finished.
       * Result will be the first item in the array that passes the truth test
       * (iteratee) or the value `undefined` if none passed. Invoked with
       * (err, result).
       * @returns A Promise, if no callback is passed
       * @example
       *
       * async.detect(['file1','file2','file3'], function(filePath, callback) {
       *     fs.access(filePath, function(err) {
       *         callback(null, !err)
       *     });
       * }, function(err, result) {
       *     // result now equals the first file in the list that exists
       * });
       */
      function detect(coll, iteratee, callback) {
          return _createTester(bool => bool, (res, item) => item)(eachOf$1, coll, iteratee, callback)
      }
      var detect$1 = awaitify(detect, 3);
  
      /**
       * The same as [`detect`]{@link module:Collections.detect} but runs a maximum of `limit` async operations at a
       * time.
       *
       * @name detectLimit
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.detect]{@link module:Collections.detect}
       * @alias findLimit
       * @category Collections
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {number} limit - The maximum number of async operations at a time.
       * @param {AsyncFunction} iteratee - A truth test to apply to each item in `coll`.
       * The iteratee must complete with a boolean value as its result.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called as soon as any
       * iteratee returns `true`, or after all the `iteratee` functions have finished.
       * Result will be the first item in the array that passes the truth test
       * (iteratee) or the value `undefined` if none passed. Invoked with
       * (err, result).
       * @returns a Promise if no callback is passed
       */
      function detectLimit(coll, limit, iteratee, callback) {
          return _createTester(bool => bool, (res, item) => item)(eachOfLimit(limit), coll, iteratee, callback)
      }
      var detectLimit$1 = awaitify(detectLimit, 4);
  
      /**
       * The same as [`detect`]{@link module:Collections.detect} but runs only a single async operation at a time.
       *
       * @name detectSeries
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.detect]{@link module:Collections.detect}
       * @alias findSeries
       * @category Collections
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - A truth test to apply to each item in `coll`.
       * The iteratee must complete with a boolean value as its result.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called as soon as any
       * iteratee returns `true`, or after all the `iteratee` functions have finished.
       * Result will be the first item in the array that passes the truth test
       * (iteratee) or the value `undefined` if none passed. Invoked with
       * (err, result).
       * @returns a Promise if no callback is passed
       */
      function detectSeries(coll, iteratee, callback) {
          return _createTester(bool => bool, (res, item) => item)(eachOfLimit(1), coll, iteratee, callback)
      }
  
      var detectSeries$1 = awaitify(detectSeries, 3);
  
      function consoleFunc(name) {
          return (fn, ...args) => wrapAsync(fn)(...args, (err, ...resultArgs) => {
              if (typeof console === 'object') {
                  if (err) {
                      if (console.error) {
                          console.error(err);
                      }
                  } else if (console[name]) {
                      resultArgs.forEach(x => console[name](x));
                  }
              }
          })
      }
  
      /**
       * Logs the result of an [`async` function]{@link AsyncFunction} to the
       * `console` using `console.dir` to display the properties of the resulting object.
       * Only works in Node.js or in browsers that support `console.dir` and
       * `console.error` (such as FF and Chrome).
       * If multiple arguments are returned from the async function,
       * `console.dir` is called on each argument in order.
       *
       * @name dir
       * @static
       * @memberOf module:Utils
       * @method
       * @category Util
       * @param {AsyncFunction} function - The function you want to eventually apply
       * all arguments to.
       * @param {...*} arguments... - Any number of arguments to apply to the function.
       * @example
       *
       * // in a module
       * var hello = function(name, callback) {
       *     setTimeout(function() {
       *         callback(null, {hello: name});
       *     }, 1000);
       * };
       *
       * // in the node repl
       * node> async.dir(hello, 'world');
       * {hello: 'world'}
       */
      var dir = consoleFunc('dir');
  
      /**
       * The post-check version of [`whilst`]{@link module:ControlFlow.whilst}. To reflect the difference in
       * the order of operations, the arguments `test` and `iteratee` are switched.
       *
       * `doWhilst` is to `whilst` as `do while` is to `while` in plain JavaScript.
       *
       * @name doWhilst
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @see [async.whilst]{@link module:ControlFlow.whilst}
       * @category Control Flow
       * @param {AsyncFunction} iteratee - A function which is called each time `test`
       * passes. Invoked with (callback).
       * @param {AsyncFunction} test - asynchronous truth test to perform after each
       * execution of `iteratee`. Invoked with (...args, callback), where `...args` are the
       * non-error args from the previous callback of `iteratee`.
       * @param {Function} [callback] - A callback which is called after the test
       * function has failed and repeated execution of `iteratee` has stopped.
       * `callback` will be passed an error and any arguments passed to the final
       * `iteratee`'s callback. Invoked with (err, [results]);
       * @returns {Promise} a promise, if no callback is passed
       */
      function doWhilst(iteratee, test, callback) {
          callback = onlyOnce(callback);
          var _fn = wrapAsync(iteratee);
          var _test = wrapAsync(test);
          var results;
  
          function next(err, ...args) {
              if (err) return callback(err);
              if (err === false) return;
              results = args;
              _test(...args, check);
          }
  
          function check(err, truth) {
              if (err) return callback(err);
              if (err === false) return;
              if (!truth) return callback(null, ...results);
              _fn(next);
          }
  
          return check(null, true);
      }
  
      var doWhilst$1 = awaitify(doWhilst, 3);
  
      /**
       * Like ['doWhilst']{@link module:ControlFlow.doWhilst}, except the `test` is inverted. Note the
       * argument ordering differs from `until`.
       *
       * @name doUntil
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @see [async.doWhilst]{@link module:ControlFlow.doWhilst}
       * @category Control Flow
       * @param {AsyncFunction} iteratee - An async function which is called each time
       * `test` fails. Invoked with (callback).
       * @param {AsyncFunction} test - asynchronous truth test to perform after each
       * execution of `iteratee`. Invoked with (...args, callback), where `...args` are the
       * non-error args from the previous callback of `iteratee`
       * @param {Function} [callback] - A callback which is called after the test
       * function has passed and repeated execution of `iteratee` has stopped. `callback`
       * will be passed an error and any arguments passed to the final `iteratee`'s
       * callback. Invoked with (err, [results]);
       * @returns {Promise} a promise, if no callback is passed
       */
      function doUntil(iteratee, test, callback) {
          const _test = wrapAsync(test);
          return doWhilst$1(iteratee, (...args) => {
              const cb = args.pop();
              _test(...args, (err, truth) => cb (err, !truth));
          }, callback);
      }
  
      function _withoutIndex(iteratee) {
          return (value, index, callback) => iteratee(value, callback);
      }
  
      /**
       * Applies the function `iteratee` to each item in `coll`, in parallel.
       * The `iteratee` is called with an item from the list, and a callback for when
       * it has finished. If the `iteratee` passes an error to its `callback`, the
       * main `callback` (for the `each` function) is immediately called with the
       * error.
       *
       * Note, that since this function applies `iteratee` to each item in parallel,
       * there is no guarantee that the iteratee functions will complete in order.
       *
       * @name each
       * @static
       * @memberOf module:Collections
       * @method
       * @alias forEach
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - An async function to apply to
       * each item in `coll`. Invoked with (item, callback).
       * The array index is not passed to the iteratee.
       * If you need the index, use `eachOf`.
       * @param {Function} [callback] - A callback which is called when all
       * `iteratee` functions have finished, or an error occurs. Invoked with (err).
       * @returns {Promise} a promise, if a callback is omitted
       * @example
       *
       * // assuming openFiles is an array of file names and saveFile is a function
       * // to save the modified contents of that file:
       *
       * async.each(openFiles, saveFile, function(err){
       *   // if any of the saves produced an error, err would equal that error
       * });
       *
       * // assuming openFiles is an array of file names
       * async.each(openFiles, function(file, callback) {
       *
       *     // Perform operation on file here.
       *     console.log('Processing file ' + file);
       *
       *     if( file.length > 32 ) {
       *       console.log('This file name is too long');
       *       callback('File name too long');
       *     } else {
       *       // Do work to process file here
       *       console.log('File processed');
       *       callback();
       *     }
       * }, function(err) {
       *     // if any of the file processing produced an error, err would equal that error
       *     if( err ) {
       *       // One of the iterations produced an error.
       *       // All processing will now stop.
       *       console.log('A file failed to process');
       *     } else {
       *       console.log('All files have been processed successfully');
       *     }
       * });
       */
      function eachLimit(coll, iteratee, callback) {
          return eachOf$1(coll, _withoutIndex(wrapAsync(iteratee)), callback);
      }
  
      var each = awaitify(eachLimit, 3);
  
      /**
       * The same as [`each`]{@link module:Collections.each} but runs a maximum of `limit` async operations at a time.
       *
       * @name eachLimit
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.each]{@link module:Collections.each}
       * @alias forEachLimit
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {number} limit - The maximum number of async operations at a time.
       * @param {AsyncFunction} iteratee - An async function to apply to each item in
       * `coll`.
       * The array index is not passed to the iteratee.
       * If you need the index, use `eachOfLimit`.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called when all
       * `iteratee` functions have finished, or an error occurs. Invoked with (err).
       * @returns {Promise} a promise, if a callback is omitted
       */
      function eachLimit$1(coll, limit, iteratee, callback) {
          return eachOfLimit(limit)(coll, _withoutIndex(wrapAsync(iteratee)), callback);
      }
      var eachLimit$2 = awaitify(eachLimit$1, 4);
  
      /**
       * The same as [`each`]{@link module:Collections.each} but runs only a single async operation at a time.
       *
       * Note, that unlike [`each`]{@link module:Collections.each}, this function applies iteratee to each item
       * in series and therefore the iteratee functions will complete in order.
  
       * @name eachSeries
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.each]{@link module:Collections.each}
       * @alias forEachSeries
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - An async function to apply to each
       * item in `coll`.
       * The array index is not passed to the iteratee.
       * If you need the index, use `eachOfSeries`.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called when all
       * `iteratee` functions have finished, or an error occurs. Invoked with (err).
       * @returns {Promise} a promise, if a callback is omitted
       */
      function eachSeries(coll, iteratee, callback) {
          return eachLimit$2(coll, 1, iteratee, callback)
      }
      var eachSeries$1 = awaitify(eachSeries, 3);
  
      /**
       * Wrap an async function and ensure it calls its callback on a later tick of
       * the event loop.  If the function already calls its callback on a next tick,
       * no extra deferral is added. This is useful for preventing stack overflows
       * (`RangeError: Maximum call stack size exceeded`) and generally keeping
       * [Zalgo](http://blog.izs.me/post/59142742143/designing-apis-for-asynchrony)
       * contained. ES2017 `async` functions are returned as-is -- they are immune
       * to Zalgo's corrupting influences, as they always resolve on a later tick.
       *
       * @name ensureAsync
       * @static
       * @memberOf module:Utils
       * @method
       * @category Util
       * @param {AsyncFunction} fn - an async function, one that expects a node-style
       * callback as its last argument.
       * @returns {AsyncFunction} Returns a wrapped function with the exact same call
       * signature as the function passed in.
       * @example
       *
       * function sometimesAsync(arg, callback) {
       *     if (cache[arg]) {
       *         return callback(null, cache[arg]); // this would be synchronous!!
       *     } else {
       *         doSomeIO(arg, callback); // this IO would be asynchronous
       *     }
       * }
       *
       * // this has a risk of stack overflows if many results are cached in a row
       * async.mapSeries(args, sometimesAsync, done);
       *
       * // this will defer sometimesAsync's callback if necessary,
       * // preventing stack overflows
       * async.mapSeries(args, async.ensureAsync(sometimesAsync), done);
       */
      function ensureAsync(fn) {
          if (isAsync(fn)) return fn;
          return function (...args/*, callback*/) {
              var callback = args.pop();
              var sync = true;
              args.push((...innerArgs) => {
                  if (sync) {
                      setImmediate$1(() => callback(...innerArgs));
                  } else {
                      callback(...innerArgs);
                  }
              });
              fn.apply(this, args);
              sync = false;
          };
      }
  
      /**
       * Returns `true` if every element in `coll` satisfies an async test. If any
       * iteratee call returns `false`, the main `callback` is immediately called.
       *
       * @name every
       * @static
       * @memberOf module:Collections
       * @method
       * @alias all
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - An async truth test to apply to each item
       * in the collection in parallel.
       * The iteratee must complete with a boolean result value.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished. Result will be either `true` or `false`
       * depending on the values of the async tests. Invoked with (err, result).
       * @returns {Promise} a promise, if no callback provided
       * @example
       *
       * async.every(['file1','file2','file3'], function(filePath, callback) {
       *     fs.access(filePath, function(err) {
       *         callback(null, !err)
       *     });
       * }, function(err, result) {
       *     // if result is true then every file exists
       * });
       */
      function every(coll, iteratee, callback) {
          return _createTester(bool => !bool, res => !res)(eachOf$1, coll, iteratee, callback)
      }
      var every$1 = awaitify(every, 3);
  
      /**
       * The same as [`every`]{@link module:Collections.every} but runs a maximum of `limit` async operations at a time.
       *
       * @name everyLimit
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.every]{@link module:Collections.every}
       * @alias allLimit
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {number} limit - The maximum number of async operations at a time.
       * @param {AsyncFunction} iteratee - An async truth test to apply to each item
       * in the collection in parallel.
       * The iteratee must complete with a boolean result value.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished. Result will be either `true` or `false`
       * depending on the values of the async tests. Invoked with (err, result).
       * @returns {Promise} a promise, if no callback provided
       */
      function everyLimit(coll, limit, iteratee, callback) {
          return _createTester(bool => !bool, res => !res)(eachOfLimit(limit), coll, iteratee, callback)
      }
      var everyLimit$1 = awaitify(everyLimit, 4);
  
      /**
       * The same as [`every`]{@link module:Collections.every} but runs only a single async operation at a time.
       *
       * @name everySeries
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.every]{@link module:Collections.every}
       * @alias allSeries
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - An async truth test to apply to each item
       * in the collection in series.
       * The iteratee must complete with a boolean result value.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished. Result will be either `true` or `false`
       * depending on the values of the async tests. Invoked with (err, result).
       * @returns {Promise} a promise, if no callback provided
       */
      function everySeries(coll, iteratee, callback) {
          return _createTester(bool => !bool, res => !res)(eachOfSeries$1, coll, iteratee, callback)
      }
      var everySeries$1 = awaitify(everySeries, 3);
  
      function filterArray(eachfn, arr, iteratee, callback) {
          var truthValues = new Array(arr.length);
          eachfn(arr, (x, index, iterCb) => {
              iteratee(x, (err, v) => {
                  truthValues[index] = !!v;
                  iterCb(err);
              });
          }, err => {
              if (err) return callback(err);
              var results = [];
              for (var i = 0; i < arr.length; i++) {
                  if (truthValues[i]) results.push(arr[i]);
              }
              callback(null, results);
          });
      }
  
      function filterGeneric(eachfn, coll, iteratee, callback) {
          var results = [];
          eachfn(coll, (x, index, iterCb) => {
              iteratee(x, (err, v) => {
                  if (err) return iterCb(err);
                  if (v) {
                      results.push({index, value: x});
                  }
                  iterCb(err);
              });
          }, err => {
              if (err) return callback(err);
              callback(null, results
                  .sort((a, b) => a.index - b.index)
                  .map(v => v.value));
          });
      }
  
      function _filter(eachfn, coll, iteratee, callback) {
          var filter = isArrayLike(coll) ? filterArray : filterGeneric;
          return filter(eachfn, coll, wrapAsync(iteratee), callback);
      }
  
      /**
       * Returns a new array of all the values in `coll` which pass an async truth
       * test. This operation is performed in parallel, but the results array will be
       * in the same order as the original.
       *
       * @name filter
       * @static
       * @memberOf module:Collections
       * @method
       * @alias select
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {Function} iteratee - A truth test to apply to each item in `coll`.
       * The `iteratee` is passed a `callback(err, truthValue)`, which must be called
       * with a boolean argument once it has completed. Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished. Invoked with (err, results).
       * @returns {Promise} a promise, if no callback provided
       * @example
       *
       * async.filter(['file1','file2','file3'], function(filePath, callback) {
       *     fs.access(filePath, function(err) {
       *         callback(null, !err)
       *     });
       * }, function(err, results) {
       *     // results now equals an array of the existing files
       * });
       */
      function filter (coll, iteratee, callback) {
          return _filter(eachOf$1, coll, iteratee, callback)
      }
      var filter$1 = awaitify(filter, 3);
  
      /**
       * The same as [`filter`]{@link module:Collections.filter} but runs a maximum of `limit` async operations at a
       * time.
       *
       * @name filterLimit
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.filter]{@link module:Collections.filter}
       * @alias selectLimit
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {number} limit - The maximum number of async operations at a time.
       * @param {Function} iteratee - A truth test to apply to each item in `coll`.
       * The `iteratee` is passed a `callback(err, truthValue)`, which must be called
       * with a boolean argument once it has completed. Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished. Invoked with (err, results).
       * @returns {Promise} a promise, if no callback provided
       */
      function filterLimit (coll, limit, iteratee, callback) {
          return _filter(eachOfLimit(limit), coll, iteratee, callback)
      }
      var filterLimit$1 = awaitify(filterLimit, 4);
  
      /**
       * The same as [`filter`]{@link module:Collections.filter} but runs only a single async operation at a time.
       *
       * @name filterSeries
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.filter]{@link module:Collections.filter}
       * @alias selectSeries
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {Function} iteratee - A truth test to apply to each item in `coll`.
       * The `iteratee` is passed a `callback(err, truthValue)`, which must be called
       * with a boolean argument once it has completed. Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished. Invoked with (err, results)
       * @returns {Promise} a promise, if no callback provided
       */
      function filterSeries (coll, iteratee, callback) {
          return _filter(eachOfSeries$1, coll, iteratee, callback)
      }
      var filterSeries$1 = awaitify(filterSeries, 3);
  
      /**
       * Calls the asynchronous function `fn` with a callback parameter that allows it
       * to call itself again, in series, indefinitely.
  
       * If an error is passed to the callback then `errback` is called with the
       * error, and execution stops, otherwise it will never be called.
       *
       * @name forever
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @category Control Flow
       * @param {AsyncFunction} fn - an async function to call repeatedly.
       * Invoked with (next).
       * @param {Function} [errback] - when `fn` passes an error to it's callback,
       * this function will be called, and execution stops. Invoked with (err).
       * @returns {Promise} a promise that rejects if an error occurs and an errback
       * is not passed
       * @example
       *
       * async.forever(
       *     function(next) {
       *         // next is suitable for passing to things that need a callback(err [, whatever]);
       *         // it will result in this function being called again.
       *     },
       *     function(err) {
       *         // if next is called with a value in its first parameter, it will appear
       *         // in here as 'err', and execution will stop.
       *     }
       * );
       */
      function forever(fn, errback) {
          var done = onlyOnce(errback);
          var task = wrapAsync(ensureAsync(fn));
  
          function next(err) {
              if (err) return done(err);
              if (err === false) return;
              task(next);
          }
          return next();
      }
      var forever$1 = awaitify(forever, 2);
  
      /**
       * The same as [`groupBy`]{@link module:Collections.groupBy} but runs a maximum of `limit` async operations at a time.
       *
       * @name groupByLimit
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.groupBy]{@link module:Collections.groupBy}
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {number} limit - The maximum number of async operations at a time.
       * @param {AsyncFunction} iteratee - An async function to apply to each item in
       * `coll`.
       * The iteratee should complete with a `key` to group the value under.
       * Invoked with (value, callback).
       * @param {Function} [callback] - A callback which is called when all `iteratee`
       * functions have finished, or an error occurs. Result is an `Object` whoses
       * properties are arrays of values which returned the corresponding key.
       * @returns {Promise} a promise, if no callback is passed
       */
      function groupByLimit(coll, limit, iteratee, callback) {
          var _iteratee = wrapAsync(iteratee);
          return mapLimit$1(coll, limit, (val, iterCb) => {
              _iteratee(val, (err, key) => {
                  if (err) return iterCb(err);
                  return iterCb(err, {key, val});
              });
          }, (err, mapResults) => {
              var result = {};
              // from MDN, handle object having an `hasOwnProperty` prop
              var {hasOwnProperty} = Object.prototype;
  
              for (var i = 0; i < mapResults.length; i++) {
                  if (mapResults[i]) {
                      var {key} = mapResults[i];
                      var {val} = mapResults[i];
  
                      if (hasOwnProperty.call(result, key)) {
                          result[key].push(val);
                      } else {
                          result[key] = [val];
                      }
                  }
              }
  
              return callback(err, result);
          });
      }
  
      var groupByLimit$1 = awaitify(groupByLimit, 4);
  
      /**
       * Returns a new object, where each value corresponds to an array of items, from
       * `coll`, that returned the corresponding key. That is, the keys of the object
       * correspond to the values passed to the `iteratee` callback.
       *
       * Note: Since this function applies the `iteratee` to each item in parallel,
       * there is no guarantee that the `iteratee` functions will complete in order.
       * However, the values for each key in the `result` will be in the same order as
       * the original `coll`. For Objects, the values will roughly be in the order of
       * the original Objects' keys (but this can vary across JavaScript engines).
       *
       * @name groupBy
       * @static
       * @memberOf module:Collections
       * @method
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - An async function to apply to each item in
       * `coll`.
       * The iteratee should complete with a `key` to group the value under.
       * Invoked with (value, callback).
       * @param {Function} [callback] - A callback which is called when all `iteratee`
       * functions have finished, or an error occurs. Result is an `Object` whoses
       * properties are arrays of values which returned the corresponding key.
       * @returns {Promise} a promise, if no callback is passed
       * @example
       *
       * async.groupBy(['userId1', 'userId2', 'userId3'], function(userId, callback) {
       *     db.findById(userId, function(err, user) {
       *         if (err) return callback(err);
       *         return callback(null, user.age);
       *     });
       * }, function(err, result) {
       *     // result is object containing the userIds grouped by age
       *     // e.g. { 30: ['userId1', 'userId3'], 42: ['userId2']};
       * });
       */
      function groupBy (coll, iteratee, callback) {
          return groupByLimit$1(coll, Infinity, iteratee, callback)
      }
  
      /**
       * The same as [`groupBy`]{@link module:Collections.groupBy} but runs only a single async operation at a time.
       *
       * @name groupBySeries
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.groupBy]{@link module:Collections.groupBy}
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - An async function to apply to each item in
       * `coll`.
       * The iteratee should complete with a `key` to group the value under.
       * Invoked with (value, callback).
       * @param {Function} [callback] - A callback which is called when all `iteratee`
       * functions have finished, or an error occurs. Result is an `Object` whoses
       * properties are arrays of values which returned the corresponding key.
       * @returns {Promise} a promise, if no callback is passed
       */
      function groupBySeries (coll, iteratee, callback) {
          return groupByLimit$1(coll, 1, iteratee, callback)
      }
  
      /**
       * Logs the result of an `async` function to the `console`. Only works in
       * Node.js or in browsers that support `console.log` and `console.error` (such
       * as FF and Chrome). If multiple arguments are returned from the async
       * function, `console.log` is called on each argument in order.
       *
       * @name log
       * @static
       * @memberOf module:Utils
       * @method
       * @category Util
       * @param {AsyncFunction} function - The function you want to eventually apply
       * all arguments to.
       * @param {...*} arguments... - Any number of arguments to apply to the function.
       * @example
       *
       * // in a module
       * var hello = function(name, callback) {
       *     setTimeout(function() {
       *         callback(null, 'hello ' + name);
       *     }, 1000);
       * };
       *
       * // in the node repl
       * node> async.log(hello, 'world');
       * 'hello world'
       */
      var log = consoleFunc('log');
  
      /**
       * The same as [`mapValues`]{@link module:Collections.mapValues} but runs a maximum of `limit` async operations at a
       * time.
       *
       * @name mapValuesLimit
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.mapValues]{@link module:Collections.mapValues}
       * @category Collection
       * @param {Object} obj - A collection to iterate over.
       * @param {number} limit - The maximum number of async operations at a time.
       * @param {AsyncFunction} iteratee - A function to apply to each value and key
       * in `coll`.
       * The iteratee should complete with the transformed value as its result.
       * Invoked with (value, key, callback).
       * @param {Function} [callback] - A callback which is called when all `iteratee`
       * functions have finished, or an error occurs. `result` is a new object consisting
       * of each key from `obj`, with each transformed value on the right-hand side.
       * Invoked with (err, result).
       * @returns {Promise} a promise, if no callback is passed
       */
      function mapValuesLimit(obj, limit, iteratee, callback) {
          callback = once(callback);
          var newObj = {};
          var _iteratee = wrapAsync(iteratee);
          return eachOfLimit(limit)(obj, (val, key, next) => {
              _iteratee(val, key, (err, result) => {
                  if (err) return next(err);
                  newObj[key] = result;
                  next(err);
              });
          }, err => callback(err, newObj));
      }
  
      var mapValuesLimit$1 = awaitify(mapValuesLimit, 4);
  
      /**
       * A relative of [`map`]{@link module:Collections.map}, designed for use with objects.
       *
       * Produces a new Object by mapping each value of `obj` through the `iteratee`
       * function. The `iteratee` is called each `value` and `key` from `obj` and a
       * callback for when it has finished processing. Each of these callbacks takes
       * two arguments: an `error`, and the transformed item from `obj`. If `iteratee`
       * passes an error to its callback, the main `callback` (for the `mapValues`
       * function) is immediately called with the error.
       *
       * Note, the order of the keys in the result is not guaranteed.  The keys will
       * be roughly in the order they complete, (but this is very engine-specific)
       *
       * @name mapValues
       * @static
       * @memberOf module:Collections
       * @method
       * @category Collection
       * @param {Object} obj - A collection to iterate over.
       * @param {AsyncFunction} iteratee - A function to apply to each value and key
       * in `coll`.
       * The iteratee should complete with the transformed value as its result.
       * Invoked with (value, key, callback).
       * @param {Function} [callback] - A callback which is called when all `iteratee`
       * functions have finished, or an error occurs. `result` is a new object consisting
       * of each key from `obj`, with each transformed value on the right-hand side.
       * Invoked with (err, result).
       * @returns {Promise} a promise, if no callback is passed
       * @example
       *
       * async.mapValues({
       *     f1: 'file1',
       *     f2: 'file2',
       *     f3: 'file3'
       * }, function (file, key, callback) {
       *   fs.stat(file, callback);
       * }, function(err, result) {
       *     // result is now a map of stats for each file, e.g.
       *     // {
       *     //     f1: [stats for file1],
       *     //     f2: [stats for file2],
       *     //     f3: [stats for file3]
       *     // }
       * });
       */
      function mapValues(obj, iteratee, callback) {
          return mapValuesLimit$1(obj, Infinity, iteratee, callback)
      }
  
      /**
       * The same as [`mapValues`]{@link module:Collections.mapValues} but runs only a single async operation at a time.
       *
       * @name mapValuesSeries
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.mapValues]{@link module:Collections.mapValues}
       * @category Collection
       * @param {Object} obj - A collection to iterate over.
       * @param {AsyncFunction} iteratee - A function to apply to each value and key
       * in `coll`.
       * The iteratee should complete with the transformed value as its result.
       * Invoked with (value, key, callback).
       * @param {Function} [callback] - A callback which is called when all `iteratee`
       * functions have finished, or an error occurs. `result` is a new object consisting
       * of each key from `obj`, with each transformed value on the right-hand side.
       * Invoked with (err, result).
       * @returns {Promise} a promise, if no callback is passed
       */
      function mapValuesSeries(obj, iteratee, callback) {
          return mapValuesLimit$1(obj, 1, iteratee, callback)
      }
  
      /**
       * Caches the results of an async function. When creating a hash to store
       * function results against, the callback is omitted from the hash and an
       * optional hash function can be used.
       *
       * **Note: if the async function errs, the result will not be cached and
       * subsequent calls will call the wrapped function.**
       *
       * If no hash function is specified, the first argument is used as a hash key,
       * which may work reasonably if it is a string or a data type that converts to a
       * distinct string. Note that objects and arrays will not behave reasonably.
       * Neither will cases where the other arguments are significant. In such cases,
       * specify your own hash function.
       *
       * The cache of results is exposed as the `memo` property of the function
       * returned by `memoize`.
       *
       * @name memoize
       * @static
       * @memberOf module:Utils
       * @method
       * @category Util
       * @param {AsyncFunction} fn - The async function to proxy and cache results from.
       * @param {Function} hasher - An optional function for generating a custom hash
       * for storing results. It has all the arguments applied to it apart from the
       * callback, and must be synchronous.
       * @returns {AsyncFunction} a memoized version of `fn`
       * @example
       *
       * var slow_fn = function(name, callback) {
       *     // do something
       *     callback(null, result);
       * };
       * var fn = async.memoize(slow_fn);
       *
       * // fn can now be used as if it were slow_fn
       * fn('some name', function() {
       *     // callback
       * });
       */
      function memoize(fn, hasher = v => v) {
          var memo = Object.create(null);
          var queues = Object.create(null);
          var _fn = wrapAsync(fn);
          var memoized = initialParams((args, callback) => {
              var key = hasher(...args);
              if (key in memo) {
                  setImmediate$1(() => callback(null, ...memo[key]));
              } else if (key in queues) {
                  queues[key].push(callback);
              } else {
                  queues[key] = [callback];
                  _fn(...args, (err, ...resultArgs) => {
                      // #1465 don't memoize if an error occurred
                      if (!err) {
                          memo[key] = resultArgs;
                      }
                      var q = queues[key];
                      delete queues[key];
                      for (var i = 0, l = q.length; i < l; i++) {
                          q[i](err, ...resultArgs);
                      }
                  });
              }
          });
          memoized.memo = memo;
          memoized.unmemoized = fn;
          return memoized;
      }
  
      /**
       * Calls `callback` on a later loop around the event loop. In Node.js this just
       * calls `process.nextTick`.  In the browser it will use `setImmediate` if
       * available, otherwise `setTimeout(callback, 0)`, which means other higher
       * priority events may precede the execution of `callback`.
       *
       * This is used internally for browser-compatibility purposes.
       *
       * @name nextTick
       * @static
       * @memberOf module:Utils
       * @method
       * @see [async.setImmediate]{@link module:Utils.setImmediate}
       * @category Util
       * @param {Function} callback - The function to call on a later loop around
       * the event loop. Invoked with (args...).
       * @param {...*} args... - any number of additional arguments to pass to the
       * callback on the next tick.
       * @example
       *
       * var call_order = [];
       * async.nextTick(function() {
       *     call_order.push('two');
       *     // call_order now equals ['one','two']
       * });
       * call_order.push('one');
       *
       * async.setImmediate(function (a, b, c) {
       *     // a, b, and c equal 1, 2, and 3
       * }, 1, 2, 3);
       */
      var _defer$1;
  
      if (hasNextTick) {
          _defer$1 = process.nextTick;
      } else if (hasSetImmediate) {
          _defer$1 = setImmediate;
      } else {
          _defer$1 = fallback;
      }
  
      var nextTick = wrap(_defer$1);
  
      var _parallel = awaitify((eachfn, tasks, callback) => {
          var results = isArrayLike(tasks) ? [] : {};
  
          eachfn(tasks, (task, key, taskCb) => {
              wrapAsync(task)((err, ...result) => {
                  if (result.length < 2) {
                      [result] = result;
                  }
                  results[key] = result;
                  taskCb(err);
              });
          }, err => callback(err, results));
      }, 3);
  
      /**
       * Run the `tasks` collection of functions in parallel, without waiting until
       * the previous function has completed. If any of the functions pass an error to
       * its callback, the main `callback` is immediately called with the value of the
       * error. Once the `tasks` have completed, the results are passed to the final
       * `callback` as an array.
       *
       * **Note:** `parallel` is about kicking-off I/O tasks in parallel, not about
       * parallel execution of code.  If your tasks do not use any timers or perform
       * any I/O, they will actually be executed in series.  Any synchronous setup
       * sections for each task will happen one after the other.  JavaScript remains
       * single-threaded.
       *
       * **Hint:** Use [`reflect`]{@link module:Utils.reflect} to continue the
       * execution of other tasks when a task fails.
       *
       * It is also possible to use an object instead of an array. Each property will
       * be run as a function and the results will be passed to the final `callback`
       * as an object instead of an array. This can be a more readable way of handling
       * results from {@link async.parallel}.
       *
       * @name parallel
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @category Control Flow
       * @param {Array|Iterable|AsyncIterable|Object} tasks - A collection of
       * [async functions]{@link AsyncFunction} to run.
       * Each async function can complete with any number of optional `result` values.
       * @param {Function} [callback] - An optional callback to run once all the
       * functions have completed successfully. This function gets a results array
       * (or object) containing all the result arguments passed to the task callbacks.
       * Invoked with (err, results).
       * @returns {Promise} a promise, if a callback is not passed
       *
       * @example
       * async.parallel([
       *     function(callback) {
       *         setTimeout(function() {
       *             callback(null, 'one');
       *         }, 200);
       *     },
       *     function(callback) {
       *         setTimeout(function() {
       *             callback(null, 'two');
       *         }, 100);
       *     }
       * ],
       * // optional callback
       * function(err, results) {
       *     // the results array will equal ['one','two'] even though
       *     // the second function had a shorter timeout.
       * });
       *
       * // an example using an object instead of an array
       * async.parallel({
       *     one: function(callback) {
       *         setTimeout(function() {
       *             callback(null, 1);
       *         }, 200);
       *     },
       *     two: function(callback) {
       *         setTimeout(function() {
       *             callback(null, 2);
       *         }, 100);
       *     }
       * }, function(err, results) {
       *     // results is now equals to: {one: 1, two: 2}
       * });
       */
      function parallel(tasks, callback) {
          return _parallel(eachOf$1, tasks, callback);
      }
  
      /**
       * The same as [`parallel`]{@link module:ControlFlow.parallel} but runs a maximum of `limit` async operations at a
       * time.
       *
       * @name parallelLimit
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @see [async.parallel]{@link module:ControlFlow.parallel}
       * @category Control Flow
       * @param {Array|Iterable|AsyncIterable|Object} tasks - A collection of
       * [async functions]{@link AsyncFunction} to run.
       * Each async function can complete with any number of optional `result` values.
       * @param {number} limit - The maximum number of async operations at a time.
       * @param {Function} [callback] - An optional callback to run once all the
       * functions have completed successfully. This function gets a results array
       * (or object) containing all the result arguments passed to the task callbacks.
       * Invoked with (err, results).
       * @returns {Promise} a promise, if a callback is not passed
       */
      function parallelLimit(tasks, limit, callback) {
          return _parallel(eachOfLimit(limit), tasks, callback);
      }
  
      /**
       * A queue of tasks for the worker function to complete.
       * @typedef {Iterable} QueueObject
       * @memberOf module:ControlFlow
       * @property {Function} length - a function returning the number of items
       * waiting to be processed. Invoke with `queue.length()`.
       * @property {boolean} started - a boolean indicating whether or not any
       * items have been pushed and processed by the queue.
       * @property {Function} running - a function returning the number of items
       * currently being processed. Invoke with `queue.running()`.
       * @property {Function} workersList - a function returning the array of items
       * currently being processed. Invoke with `queue.workersList()`.
       * @property {Function} idle - a function returning false if there are items
       * waiting or being processed, or true if not. Invoke with `queue.idle()`.
       * @property {number} concurrency - an integer for determining how many `worker`
       * functions should be run in parallel. This property can be changed after a
       * `queue` is created to alter the concurrency on-the-fly.
       * @property {number} payload - an integer that specifies how many items are
       * passed to the worker function at a time. only applies if this is a
       * [cargo]{@link module:ControlFlow.cargo} object
       * @property {Function} push - add a new task to the `queue`. Calls `callback`
       * once the `worker` has finished processing the task. Instead of a single task,
       * a `tasks` array can be submitted. The respective callback is used for every
       * task in the list. Invoke with `queue.push(task, [callback])`,
       * @property {Function} unshift - add a new task to the front of the `queue`.
       * Invoke with `queue.unshift(task, [callback])`.
       * @property {Function} remove - remove items from the queue that match a test
       * function.  The test function will be passed an object with a `data` property,
       * and a `priority` property, if this is a
       * [priorityQueue]{@link module:ControlFlow.priorityQueue} object.
       * Invoked with `queue.remove(testFn)`, where `testFn` is of the form
       * `function ({data, priority}) {}` and returns a Boolean.
       * @property {Function} saturated - a function that sets a callback that is
       * called when the number of running workers hits the `concurrency` limit, and
       * further tasks will be queued.  If the callback is omitted, `q.saturated()`
       * returns a promise for the next occurrence.
       * @property {Function} unsaturated - a function that sets a callback that is
       * called when the number of running workers is less than the `concurrency` &
       * `buffer` limits, and further tasks will not be queued. If the callback is
       * omitted, `q.unsaturated()` returns a promise for the next occurrence.
       * @property {number} buffer - A minimum threshold buffer in order to say that
       * the `queue` is `unsaturated`.
       * @property {Function} empty - a function that sets a callback that is called
       * when the last item from the `queue` is given to a `worker`. If the callback
       * is omitted, `q.empty()` returns a promise for the next occurrence.
       * @property {Function} drain - a function that sets a callback that is called
       * when the last item from the `queue` has returned from the `worker`. If the
       * callback is omitted, `q.drain()` returns a promise for the next occurrence.
       * @property {Function} error - a function that sets a callback that is called
       * when a task errors. Has the signature `function(error, task)`. If the
       * callback is omitted, `error()` returns a promise that rejects on the next
       * error.
       * @property {boolean} paused - a boolean for determining whether the queue is
       * in a paused state.
       * @property {Function} pause - a function that pauses the processing of tasks
       * until `resume()` is called. Invoke with `queue.pause()`.
       * @property {Function} resume - a function that resumes the processing of
       * queued tasks when the queue is paused. Invoke with `queue.resume()`.
       * @property {Function} kill - a function that removes the `drain` callback and
       * empties remaining tasks from the queue forcing it to go idle. No more tasks
       * should be pushed to the queue after calling this function. Invoke with `queue.kill()`.
       *
       * @example
       * const q = aync.queue(worker, 2)
       * q.push(item1)
       * q.push(item2)
       * q.push(item3)
       * // queues are iterable, spread into an array to inspect
       * const items = [...q] // [item1, item2, item3]
       * // or use for of
       * for (let item of q) {
       *     console.log(item)
       * }
       *
       * q.drain(() => {
       *     console.log('all done')
       * })
       * // or
       * await q.drain()
       */
  
      /**
       * Creates a `queue` object with the specified `concurrency`. Tasks added to the
       * `queue` are processed in parallel (up to the `concurrency` limit). If all
       * `worker`s are in progress, the task is queued until one becomes available.
       * Once a `worker` completes a `task`, that `task`'s callback is called.
       *
       * @name queue
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @category Control Flow
       * @param {AsyncFunction} worker - An async function for processing a queued task.
       * If you want to handle errors from an individual task, pass a callback to
       * `q.push()`. Invoked with (task, callback).
       * @param {number} [concurrency=1] - An `integer` for determining how many
       * `worker` functions should be run in parallel.  If omitted, the concurrency
       * defaults to `1`.  If the concurrency is `0`, an error is thrown.
       * @returns {module:ControlFlow.QueueObject} A queue object to manage the tasks. Callbacks can be
       * attached as certain properties to listen for specific events during the
       * lifecycle of the queue.
       * @example
       *
       * // create a queue object with concurrency 2
       * var q = async.queue(function(task, callback) {
       *     console.log('hello ' + task.name);
       *     callback();
       * }, 2);
       *
       * // assign a callback
       * q.drain(function() {
       *     console.log('all items have been processed');
       * });
       * // or await the end
       * await q.drain()
       *
       * // assign an error callback
       * q.error(function(err, task) {
       *     console.error('task experienced an error');
       * });
       *
       * // add some items to the queue
       * q.push({name: 'foo'}, function(err) {
       *     console.log('finished processing foo');
       * });
       * // callback is optional
       * q.push({name: 'bar'});
       *
       * // add some items to the queue (batch-wise)
       * q.push([{name: 'baz'},{name: 'bay'},{name: 'bax'}], function(err) {
       *     console.log('finished processing item');
       * });
       *
       * // add some items to the front of the queue
       * q.unshift({name: 'bar'}, function (err) {
       *     console.log('finished processing bar');
       * });
       */
      function queue$1 (worker, concurrency) {
          var _worker = wrapAsync(worker);
          return queue((items, cb) => {
              _worker(items[0], cb);
          }, concurrency, 1);
      }
  
      // Binary min-heap implementation used for priority queue.
      // Implementation is stable, i.e. push time is considered for equal priorities
      class Heap {
          constructor() {
              this.heap = [];
              this.pushCount = Number.MIN_SAFE_INTEGER;
          }
  
          get length() {
              return this.heap.length;
          }
  
          empty () {
              this.heap = [];
              return this;
          }
  
          percUp(index) {
              let p;
  
              while (index > 0 && smaller(this.heap[index], this.heap[p=parent(index)])) {
                  let t = this.heap[index];
                  this.heap[index] = this.heap[p];
                  this.heap[p] = t;
  
                  index = p;
              }
          }
  
          percDown(index) {
              let l;
  
              while ((l=leftChi(index)) < this.heap.length) {
                  if (l+1 < this.heap.length && smaller(this.heap[l+1], this.heap[l])) {
                      l = l+1;
                  }
  
                  if (smaller(this.heap[index], this.heap[l])) {
                      break;
                  }
  
                  let t = this.heap[index];
                  this.heap[index] = this.heap[l];
                  this.heap[l] = t;
  
                  index = l;
              }
          }
  
          push(node) {
              node.pushCount = ++this.pushCount;
              this.heap.push(node);
              this.percUp(this.heap.length-1);
          }
  
          unshift(node) {
              return this.heap.push(node);
          }
  
          shift() {
              let [top] = this.heap;
  
              this.heap[0] = this.heap[this.heap.length-1];
              this.heap.pop();
              this.percDown(0);
  
              return top;
          }
  
          toArray() {
              return [...this];
          }
  
          *[Symbol.iterator] () {
              for (let i = 0; i < this.heap.length; i++) {
                  yield this.heap[i].data;
              }
          }
  
          remove (testFn) {
              let j = 0;
              for (let i = 0; i < this.heap.length; i++) {
                  if (!testFn(this.heap[i])) {
                      this.heap[j] = this.heap[i];
                      j++;
                  }
              }
  
              this.heap.splice(j);
  
              for (let i = parent(this.heap.length-1); i >= 0; i--) {
                  this.percDown(i);
              }
  
              return this;
          }
      }
  
      function leftChi(i) {
          return (i<<1)+1;
      }
  
      function parent(i) {
          return ((i+1)>>1)-1;
      }
  
      function smaller(x, y) {
          if (x.priority !== y.priority) {
              return x.priority < y.priority;
          }
          else {
              return x.pushCount < y.pushCount;
          }
      }
  
      /**
       * The same as [async.queue]{@link module:ControlFlow.queue} only tasks are assigned a priority and
       * completed in ascending priority order.
       *
       * @name priorityQueue
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @see [async.queue]{@link module:ControlFlow.queue}
       * @category Control Flow
       * @param {AsyncFunction} worker - An async function for processing a queued task.
       * If you want to handle errors from an individual task, pass a callback to
       * `q.push()`.
       * Invoked with (task, callback).
       * @param {number} concurrency - An `integer` for determining how many `worker`
       * functions should be run in parallel.  If omitted, the concurrency defaults to
       * `1`.  If the concurrency is `0`, an error is thrown.
       * @returns {module:ControlFlow.QueueObject} A priorityQueue object to manage the tasks. There are two
       * differences between `queue` and `priorityQueue` objects:
       * * `push(task, priority, [callback])` - `priority` should be a number. If an
       *   array of `tasks` is given, all tasks will be assigned the same priority.
       * * The `unshift` method was removed.
       */
      function priorityQueue(worker, concurrency) {
          // Start with a normal queue
          var q = queue$1(worker, concurrency);
  
          q._tasks = new Heap();
  
          // Override push to accept second parameter representing priority
          q.push = function(data, priority = 0, callback = () => {}) {
              if (typeof callback !== 'function') {
                  throw new Error('task callback must be a function');
              }
              q.started = true;
              if (!Array.isArray(data)) {
                  data = [data];
              }
              if (data.length === 0 && q.idle()) {
                  // call drain immediately if there are no tasks
                  return setImmediate$1(() => q.drain());
              }
  
              for (var i = 0, l = data.length; i < l; i++) {
                  var item = {
                      data: data[i],
                      priority,
                      callback
                  };
  
                  q._tasks.push(item);
              }
  
              setImmediate$1(q.process);
          };
  
          // Remove unshift function
          delete q.unshift;
  
          return q;
      }
  
      /**
       * Runs the `tasks` array of functions in parallel, without waiting until the
       * previous function has completed. Once any of the `tasks` complete or pass an
       * error to its callback, the main `callback` is immediately called. It's
       * equivalent to `Promise.race()`.
       *
       * @name race
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @category Control Flow
       * @param {Array} tasks - An array containing [async functions]{@link AsyncFunction}
       * to run. Each function can complete with an optional `result` value.
       * @param {Function} callback - A callback to run once any of the functions have
       * completed. This function gets an error or result from the first function that
       * completed. Invoked with (err, result).
       * @returns undefined
       * @example
       *
       * async.race([
       *     function(callback) {
       *         setTimeout(function() {
       *             callback(null, 'one');
       *         }, 200);
       *     },
       *     function(callback) {
       *         setTimeout(function() {
       *             callback(null, 'two');
       *         }, 100);
       *     }
       * ],
       * // main callback
       * function(err, result) {
       *     // the result will be equal to 'two' as it finishes earlier
       * });
       */
      function race(tasks, callback) {
          callback = once(callback);
          if (!Array.isArray(tasks)) return callback(new TypeError('First argument to race must be an array of functions'));
          if (!tasks.length) return callback();
          for (var i = 0, l = tasks.length; i < l; i++) {
              wrapAsync(tasks[i])(callback);
          }
      }
  
      var race$1 = awaitify(race, 2);
  
      /**
       * Same as [`reduce`]{@link module:Collections.reduce}, only operates on `array` in reverse order.
       *
       * @name reduceRight
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.reduce]{@link module:Collections.reduce}
       * @alias foldr
       * @category Collection
       * @param {Array} array - A collection to iterate over.
       * @param {*} memo - The initial state of the reduction.
       * @param {AsyncFunction} iteratee - A function applied to each item in the
       * array to produce the next step in the reduction.
       * The `iteratee` should complete with the next state of the reduction.
       * If the iteratee complete with an error, the reduction is stopped and the
       * main `callback` is immediately called with the error.
       * Invoked with (memo, item, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished. Result is the reduced value. Invoked with
       * (err, result).
       * @returns {Promise} a promise, if no callback is passed
       */
      function reduceRight (array, memo, iteratee, callback) {
          var reversed = [...array].reverse();
          return reduce$1(reversed, memo, iteratee, callback);
      }
  
      /**
       * Wraps the async function in another function that always completes with a
       * result object, even when it errors.
       *
       * The result object has either the property `error` or `value`.
       *
       * @name reflect
       * @static
       * @memberOf module:Utils
       * @method
       * @category Util
       * @param {AsyncFunction} fn - The async function you want to wrap
       * @returns {Function} - A function that always passes null to it's callback as
       * the error. The second argument to the callback will be an `object` with
       * either an `error` or a `value` property.
       * @example
       *
       * async.parallel([
       *     async.reflect(function(callback) {
       *         // do some stuff ...
       *         callback(null, 'one');
       *     }),
       *     async.reflect(function(callback) {
       *         // do some more stuff but error ...
       *         callback('bad stuff happened');
       *     }),
       *     async.reflect(function(callback) {
       *         // do some more stuff ...
       *         callback(null, 'two');
       *     })
       * ],
       * // optional callback
       * function(err, results) {
       *     // values
       *     // results[0].value = 'one'
       *     // results[1].error = 'bad stuff happened'
       *     // results[2].value = 'two'
       * });
       */
      function reflect(fn) {
          var _fn = wrapAsync(fn);
          return initialParams(function reflectOn(args, reflectCallback) {
              args.push((error, ...cbArgs) => {
                  let retVal = {};
                  if (error) {
                      retVal.error = error;
                  }
                  if (cbArgs.length > 0){
                      var value = cbArgs;
                      if (cbArgs.length <= 1) {
                          [value] = cbArgs;
                      }
                      retVal.value = value;
                  }
                  reflectCallback(null, retVal);
              });
  
              return _fn.apply(this, args);
          });
      }
  
      /**
       * A helper function that wraps an array or an object of functions with `reflect`.
       *
       * @name reflectAll
       * @static
       * @memberOf module:Utils
       * @method
       * @see [async.reflect]{@link module:Utils.reflect}
       * @category Util
       * @param {Array|Object|Iterable} tasks - The collection of
       * [async functions]{@link AsyncFunction} to wrap in `async.reflect`.
       * @returns {Array} Returns an array of async functions, each wrapped in
       * `async.reflect`
       * @example
       *
       * let tasks = [
       *     function(callback) {
       *         setTimeout(function() {
       *             callback(null, 'one');
       *         }, 200);
       *     },
       *     function(callback) {
       *         // do some more stuff but error ...
       *         callback(new Error('bad stuff happened'));
       *     },
       *     function(callback) {
       *         setTimeout(function() {
       *             callback(null, 'two');
       *         }, 100);
       *     }
       * ];
       *
       * async.parallel(async.reflectAll(tasks),
       * // optional callback
       * function(err, results) {
       *     // values
       *     // results[0].value = 'one'
       *     // results[1].error = Error('bad stuff happened')
       *     // results[2].value = 'two'
       * });
       *
       * // an example using an object instead of an array
       * let tasks = {
       *     one: function(callback) {
       *         setTimeout(function() {
       *             callback(null, 'one');
       *         }, 200);
       *     },
       *     two: function(callback) {
       *         callback('two');
       *     },
       *     three: function(callback) {
       *         setTimeout(function() {
       *             callback(null, 'three');
       *         }, 100);
       *     }
       * };
       *
       * async.parallel(async.reflectAll(tasks),
       * // optional callback
       * function(err, results) {
       *     // values
       *     // results.one.value = 'one'
       *     // results.two.error = 'two'
       *     // results.three.value = 'three'
       * });
       */
      function reflectAll(tasks) {
          var results;
          if (Array.isArray(tasks)) {
              results = tasks.map(reflect);
          } else {
              results = {};
              Object.keys(tasks).forEach(key => {
                  results[key] = reflect.call(this, tasks[key]);
              });
          }
          return results;
      }
  
      function reject(eachfn, arr, _iteratee, callback) {
          const iteratee = wrapAsync(_iteratee);
          return _filter(eachfn, arr, (value, cb) => {
              iteratee(value, (err, v) => {
                  cb(err, !v);
              });
          }, callback);
      }
  
      /**
       * The opposite of [`filter`]{@link module:Collections.filter}. Removes values that pass an `async` truth test.
       *
       * @name reject
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.filter]{@link module:Collections.filter}
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {Function} iteratee - An async truth test to apply to each item in
       * `coll`.
       * The should complete with a boolean value as its `result`.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished. Invoked with (err, results).
       * @returns {Promise} a promise, if no callback is passed
       * @example
       *
       * async.reject(['file1','file2','file3'], function(filePath, callback) {
       *     fs.access(filePath, function(err) {
       *         callback(null, !err)
       *     });
       * }, function(err, results) {
       *     // results now equals an array of missing files
       *     createFiles(results);
       * });
       */
      function reject$1 (coll, iteratee, callback) {
          return reject(eachOf$1, coll, iteratee, callback)
      }
      var reject$2 = awaitify(reject$1, 3);
  
      /**
       * The same as [`reject`]{@link module:Collections.reject} but runs a maximum of `limit` async operations at a
       * time.
       *
       * @name rejectLimit
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.reject]{@link module:Collections.reject}
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {number} limit - The maximum number of async operations at a time.
       * @param {Function} iteratee - An async truth test to apply to each item in
       * `coll`.
       * The should complete with a boolean value as its `result`.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished. Invoked with (err, results).
       * @returns {Promise} a promise, if no callback is passed
       */
      function rejectLimit (coll, limit, iteratee, callback) {
          return reject(eachOfLimit(limit), coll, iteratee, callback)
      }
      var rejectLimit$1 = awaitify(rejectLimit, 4);
  
      /**
       * The same as [`reject`]{@link module:Collections.reject} but runs only a single async operation at a time.
       *
       * @name rejectSeries
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.reject]{@link module:Collections.reject}
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {Function} iteratee - An async truth test to apply to each item in
       * `coll`.
       * The should complete with a boolean value as its `result`.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished. Invoked with (err, results).
       * @returns {Promise} a promise, if no callback is passed
       */
      function rejectSeries (coll, iteratee, callback) {
          return reject(eachOfSeries$1, coll, iteratee, callback)
      }
      var rejectSeries$1 = awaitify(rejectSeries, 3);
  
      function constant$1(value) {
          return function () {
              return value;
          }
      }
  
      /**
       * Attempts to get a successful response from `task` no more than `times` times
       * before returning an error. If the task is successful, the `callback` will be
       * passed the result of the successful task. If all attempts fail, the callback
       * will be passed the error and result (if any) of the final attempt.
       *
       * @name retry
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @category Control Flow
       * @see [async.retryable]{@link module:ControlFlow.retryable}
       * @param {Object|number} [opts = {times: 5, interval: 0}| 5] - Can be either an
       * object with `times` and `interval` or a number.
       * * `times` - The number of attempts to make before giving up.  The default
       *   is `5`.
       * * `interval` - The time to wait between retries, in milliseconds.  The
       *   default is `0`. The interval may also be specified as a function of the
       *   retry count (see example).
       * * `errorFilter` - An optional synchronous function that is invoked on
       *   erroneous result. If it returns `true` the retry attempts will continue;
       *   if the function returns `false` the retry flow is aborted with the current
       *   attempt's error and result being returned to the final callback.
       *   Invoked with (err).
       * * If `opts` is a number, the number specifies the number of times to retry,
       *   with the default interval of `0`.
       * @param {AsyncFunction} task - An async function to retry.
       * Invoked with (callback).
       * @param {Function} [callback] - An optional callback which is called when the
       * task has succeeded, or after the final failed attempt. It receives the `err`
       * and `result` arguments of the last attempt at completing the `task`. Invoked
       * with (err, results).
       * @returns {Promise} a promise if no callback provided
       *
       * @example
       *
       * // The `retry` function can be used as a stand-alone control flow by passing
       * // a callback, as shown below:
       *
       * // try calling apiMethod 3 times
       * async.retry(3, apiMethod, function(err, result) {
       *     // do something with the result
       * });
       *
       * // try calling apiMethod 3 times, waiting 200 ms between each retry
       * async.retry({times: 3, interval: 200}, apiMethod, function(err, result) {
       *     // do something with the result
       * });
       *
       * // try calling apiMethod 10 times with exponential backoff
       * // (i.e. intervals of 100, 200, 400, 800, 1600, ... milliseconds)
       * async.retry({
       *   times: 10,
       *   interval: function(retryCount) {
       *     return 50 * Math.pow(2, retryCount);
       *   }
       * }, apiMethod, function(err, result) {
       *     // do something with the result
       * });
       *
       * // try calling apiMethod the default 5 times no delay between each retry
       * async.retry(apiMethod, function(err, result) {
       *     // do something with the result
       * });
       *
       * // try calling apiMethod only when error condition satisfies, all other
       * // errors will abort the retry control flow and return to final callback
       * async.retry({
       *   errorFilter: function(err) {
       *     return err.message === 'Temporary error'; // only retry on a specific error
       *   }
       * }, apiMethod, function(err, result) {
       *     // do something with the result
       * });
       *
       * // to retry individual methods that are not as reliable within other
       * // control flow functions, use the `retryable` wrapper:
       * async.auto({
       *     users: api.getUsers.bind(api),
       *     payments: async.retryable(3, api.getPayments.bind(api))
       * }, function(err, results) {
       *     // do something with the results
       * });
       *
       */
      const DEFAULT_TIMES = 5;
      const DEFAULT_INTERVAL = 0;
  
      function retry(opts, task, callback) {
          var options = {
              times: DEFAULT_TIMES,
              intervalFunc: constant$1(DEFAULT_INTERVAL)
          };
  
          if (arguments.length < 3 && typeof opts === 'function') {
              callback = task || promiseCallback();
              task = opts;
          } else {
              parseTimes(options, opts);
              callback = callback || promiseCallback();
          }
  
          if (typeof task !== 'function') {
              throw new Error("Invalid arguments for async.retry");
          }
  
          var _task = wrapAsync(task);
  
          var attempt = 1;
          function retryAttempt() {
              _task((err, ...args) => {
                  if (err === false) return
                  if (err && attempt++ < options.times &&
                      (typeof options.errorFilter != 'function' ||
                          options.errorFilter(err))) {
                      setTimeout(retryAttempt, options.intervalFunc(attempt - 1));
                  } else {
                      callback(err, ...args);
                  }
              });
          }
  
          retryAttempt();
          return callback[PROMISE_SYMBOL]
      }
  
      function parseTimes(acc, t) {
          if (typeof t === 'object') {
              acc.times = +t.times || DEFAULT_TIMES;
  
              acc.intervalFunc = typeof t.interval === 'function' ?
                  t.interval :
                  constant$1(+t.interval || DEFAULT_INTERVAL);
  
              acc.errorFilter = t.errorFilter;
          } else if (typeof t === 'number' || typeof t === 'string') {
              acc.times = +t || DEFAULT_TIMES;
          } else {
              throw new Error("Invalid arguments for async.retry");
          }
      }
  
      /**
       * A close relative of [`retry`]{@link module:ControlFlow.retry}.  This method
       * wraps a task and makes it retryable, rather than immediately calling it
       * with retries.
       *
       * @name retryable
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @see [async.retry]{@link module:ControlFlow.retry}
       * @category Control Flow
       * @param {Object|number} [opts = {times: 5, interval: 0}| 5] - optional
       * options, exactly the same as from `retry`, except for a `opts.arity` that
       * is the arity of the `task` function, defaulting to `task.length`
       * @param {AsyncFunction} task - the asynchronous function to wrap.
       * This function will be passed any arguments passed to the returned wrapper.
       * Invoked with (...args, callback).
       * @returns {AsyncFunction} The wrapped function, which when invoked, will
       * retry on an error, based on the parameters specified in `opts`.
       * This function will accept the same parameters as `task`.
       * @example
       *
       * async.auto({
       *     dep1: async.retryable(3, getFromFlakyService),
       *     process: ["dep1", async.retryable(3, function (results, cb) {
       *         maybeProcessData(results.dep1, cb);
       *     })]
       * }, callback);
       */
      function retryable (opts, task) {
          if (!task) {
              task = opts;
              opts = null;
          }
          let arity = (opts && opts.arity) || task.length;
          if (isAsync(task)) {
              arity += 1;
          }
          var _task = wrapAsync(task);
          return initialParams((args, callback) => {
              if (args.length < arity - 1 || callback == null) {
                  args.push(callback);
                  callback = promiseCallback();
              }
              function taskFn(cb) {
                  _task(...args, cb);
              }
  
              if (opts) retry(opts, taskFn, callback);
              else retry(taskFn, callback);
  
              return callback[PROMISE_SYMBOL]
          });
      }
  
      /**
       * Run the functions in the `tasks` collection in series, each one running once
       * the previous function has completed. If any functions in the series pass an
       * error to its callback, no more functions are run, and `callback` is
       * immediately called with the value of the error. Otherwise, `callback`
       * receives an array of results when `tasks` have completed.
       *
       * It is also possible to use an object instead of an array. Each property will
       * be run as a function, and the results will be passed to the final `callback`
       * as an object instead of an array. This can be a more readable way of handling
       *  results from {@link async.series}.
       *
       * **Note** that while many implementations preserve the order of object
       * properties, the [ECMAScript Language Specification](http://www.ecma-international.org/ecma-262/5.1/#sec-8.6)
       * explicitly states that
       *
       * > The mechanics and order of enumerating the properties is not specified.
       *
       * So if you rely on the order in which your series of functions are executed,
       * and want this to work on all platforms, consider using an array.
       *
       * @name series
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @category Control Flow
       * @param {Array|Iterable|AsyncIterable|Object} tasks - A collection containing
       * [async functions]{@link AsyncFunction} to run in series.
       * Each function can complete with any number of optional `result` values.
       * @param {Function} [callback] - An optional callback to run once all the
       * functions have completed. This function gets a results array (or object)
       * containing all the result arguments passed to the `task` callbacks. Invoked
       * with (err, result).
       * @return {Promise} a promise, if no callback is passed
       * @example
       * async.series([
       *     function(callback) {
       *         // do some stuff ...
       *         callback(null, 'one');
       *     },
       *     function(callback) {
       *         // do some more stuff ...
       *         callback(null, 'two');
       *     }
       * ],
       * // optional callback
       * function(err, results) {
       *     // results is now equal to ['one', 'two']
       * });
       *
       * async.series({
       *     one: function(callback) {
       *         setTimeout(function() {
       *             callback(null, 1);
       *         }, 200);
       *     },
       *     two: function(callback){
       *         setTimeout(function() {
       *             callback(null, 2);
       *         }, 100);
       *     }
       * }, function(err, results) {
       *     // results is now equal to: {one: 1, two: 2}
       * });
       */
      function series(tasks, callback) {
          return _parallel(eachOfSeries$1, tasks, callback);
      }
  
      /**
       * Returns `true` if at least one element in the `coll` satisfies an async test.
       * If any iteratee call returns `true`, the main `callback` is immediately
       * called.
       *
       * @name some
       * @static
       * @memberOf module:Collections
       * @method
       * @alias any
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - An async truth test to apply to each item
       * in the collections in parallel.
       * The iteratee should complete with a boolean `result` value.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called as soon as any
       * iteratee returns `true`, or after all the iteratee functions have finished.
       * Result will be either `true` or `false` depending on the values of the async
       * tests. Invoked with (err, result).
       * @returns {Promise} a promise, if no callback provided
       * @example
       *
       * async.some(['file1','file2','file3'], function(filePath, callback) {
       *     fs.access(filePath, function(err) {
       *         callback(null, !err)
       *     });
       * }, function(err, result) {
       *     // if result is true then at least one of the files exists
       * });
       */
      function some(coll, iteratee, callback) {
          return _createTester(Boolean, res => res)(eachOf$1, coll, iteratee, callback)
      }
      var some$1 = awaitify(some, 3);
  
      /**
       * The same as [`some`]{@link module:Collections.some} but runs a maximum of `limit` async operations at a time.
       *
       * @name someLimit
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.some]{@link module:Collections.some}
       * @alias anyLimit
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {number} limit - The maximum number of async operations at a time.
       * @param {AsyncFunction} iteratee - An async truth test to apply to each item
       * in the collections in parallel.
       * The iteratee should complete with a boolean `result` value.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called as soon as any
       * iteratee returns `true`, or after all the iteratee functions have finished.
       * Result will be either `true` or `false` depending on the values of the async
       * tests. Invoked with (err, result).
       * @returns {Promise} a promise, if no callback provided
       */
      function someLimit(coll, limit, iteratee, callback) {
          return _createTester(Boolean, res => res)(eachOfLimit(limit), coll, iteratee, callback)
      }
      var someLimit$1 = awaitify(someLimit, 4);
  
      /**
       * The same as [`some`]{@link module:Collections.some} but runs only a single async operation at a time.
       *
       * @name someSeries
       * @static
       * @memberOf module:Collections
       * @method
       * @see [async.some]{@link module:Collections.some}
       * @alias anySeries
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - An async truth test to apply to each item
       * in the collections in series.
       * The iteratee should complete with a boolean `result` value.
       * Invoked with (item, callback).
       * @param {Function} [callback] - A callback which is called as soon as any
       * iteratee returns `true`, or after all the iteratee functions have finished.
       * Result will be either `true` or `false` depending on the values of the async
       * tests. Invoked with (err, result).
       * @returns {Promise} a promise, if no callback provided
       */
      function someSeries(coll, iteratee, callback) {
          return _createTester(Boolean, res => res)(eachOfSeries$1, coll, iteratee, callback)
      }
      var someSeries$1 = awaitify(someSeries, 3);
  
      /**
       * Sorts a list by the results of running each `coll` value through an async
       * `iteratee`.
       *
       * @name sortBy
       * @static
       * @memberOf module:Collections
       * @method
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {AsyncFunction} iteratee - An async function to apply to each item in
       * `coll`.
       * The iteratee should complete with a value to use as the sort criteria as
       * its `result`.
       * Invoked with (item, callback).
       * @param {Function} callback - A callback which is called after all the
       * `iteratee` functions have finished, or an error occurs. Results is the items
       * from the original `coll` sorted by the values returned by the `iteratee`
       * calls. Invoked with (err, results).
       * @returns {Promise} a promise, if no callback passed
       * @example
       *
       * async.sortBy(['file1','file2','file3'], function(file, callback) {
       *     fs.stat(file, function(err, stats) {
       *         callback(err, stats.mtime);
       *     });
       * }, function(err, results) {
       *     // results is now the original array of files sorted by
       *     // modified date
       * });
       *
       * // By modifying the callback parameter the
       * // sorting order can be influenced:
       *
       * // ascending order
       * async.sortBy([1,9,3,5], function(x, callback) {
       *     callback(null, x);
       * }, function(err,result) {
       *     // result callback
       * });
       *
       * // descending order
       * async.sortBy([1,9,3,5], function(x, callback) {
       *     callback(null, x*-1);    //<- x*-1 instead of x, turns the order around
       * }, function(err,result) {
       *     // result callback
       * });
       */
      function sortBy (coll, iteratee, callback) {
          var _iteratee = wrapAsync(iteratee);
          return map$1(coll, (x, iterCb) => {
              _iteratee(x, (err, criteria) => {
                  if (err) return iterCb(err);
                  iterCb(err, {value: x, criteria});
              });
          }, (err, results) => {
              if (err) return callback(err);
              callback(null, results.sort(comparator).map(v => v.value));
          });
  
          function comparator(left, right) {
              var a = left.criteria, b = right.criteria;
              return a < b ? -1 : a > b ? 1 : 0;
          }
      }
      var sortBy$1 = awaitify(sortBy, 3);
  
      /**
       * Sets a time limit on an asynchronous function. If the function does not call
       * its callback within the specified milliseconds, it will be called with a
       * timeout error. The code property for the error object will be `'ETIMEDOUT'`.
       *
       * @name timeout
       * @static
       * @memberOf module:Utils
       * @method
       * @category Util
       * @param {AsyncFunction} asyncFn - The async function to limit in time.
       * @param {number} milliseconds - The specified time limit.
       * @param {*} [info] - Any variable you want attached (`string`, `object`, etc)
       * to timeout Error for more information..
       * @returns {AsyncFunction} Returns a wrapped function that can be used with any
       * of the control flow functions.
       * Invoke this function with the same parameters as you would `asyncFunc`.
       * @example
       *
       * function myFunction(foo, callback) {
       *     doAsyncTask(foo, function(err, data) {
       *         // handle errors
       *         if (err) return callback(err);
       *
       *         // do some stuff ...
       *
       *         // return processed data
       *         return callback(null, data);
       *     });
       * }
       *
       * var wrapped = async.timeout(myFunction, 1000);
       *
       * // call `wrapped` as you would `myFunction`
       * wrapped({ bar: 'bar' }, function(err, data) {
       *     // if `myFunction` takes < 1000 ms to execute, `err`
       *     // and `data` will have their expected values
       *
       *     // else `err` will be an Error with the code 'ETIMEDOUT'
       * });
       */
      function timeout(asyncFn, milliseconds, info) {
          var fn = wrapAsync(asyncFn);
  
          return initialParams((args, callback) => {
              var timedOut = false;
              var timer;
  
              function timeoutCallback() {
                  var name = asyncFn.name || 'anonymous';
                  var error  = new Error('Callback function "' + name + '" timed out.');
                  error.code = 'ETIMEDOUT';
                  if (info) {
                      error.info = info;
                  }
                  timedOut = true;
                  callback(error);
              }
  
              args.push((...cbArgs) => {
                  if (!timedOut) {
                      callback(...cbArgs);
                      clearTimeout(timer);
                  }
              });
  
              // setup timer and call original function
              timer = setTimeout(timeoutCallback, milliseconds);
              fn(...args);
          });
      }
  
      function range(size) {
          var result = Array(size);
          while (size--) {
              result[size] = size;
          }
          return result;
      }
  
      /**
       * The same as [times]{@link module:ControlFlow.times} but runs a maximum of `limit` async operations at a
       * time.
       *
       * @name timesLimit
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @see [async.times]{@link module:ControlFlow.times}
       * @category Control Flow
       * @param {number} count - The number of times to run the function.
       * @param {number} limit - The maximum number of async operations at a time.
       * @param {AsyncFunction} iteratee - The async function to call `n` times.
       * Invoked with the iteration index and a callback: (n, next).
       * @param {Function} callback - see [async.map]{@link module:Collections.map}.
       * @returns {Promise} a promise, if no callback is provided
       */
      function timesLimit(count, limit, iteratee, callback) {
          var _iteratee = wrapAsync(iteratee);
          return mapLimit$1(range(count), limit, _iteratee, callback);
      }
  
      /**
       * Calls the `iteratee` function `n` times, and accumulates results in the same
       * manner you would use with [map]{@link module:Collections.map}.
       *
       * @name times
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @see [async.map]{@link module:Collections.map}
       * @category Control Flow
       * @param {number} n - The number of times to run the function.
       * @param {AsyncFunction} iteratee - The async function to call `n` times.
       * Invoked with the iteration index and a callback: (n, next).
       * @param {Function} callback - see {@link module:Collections.map}.
       * @returns {Promise} a promise, if no callback is provided
       * @example
       *
       * // Pretend this is some complicated async factory
       * var createUser = function(id, callback) {
       *     callback(null, {
       *         id: 'user' + id
       *     });
       * };
       *
       * // generate 5 users
       * async.times(5, function(n, next) {
       *     createUser(n, function(err, user) {
       *         next(err, user);
       *     });
       * }, function(err, users) {
       *     // we should now have 5 users
       * });
       */
      function times (n, iteratee, callback) {
          return timesLimit(n, Infinity, iteratee, callback)
      }
  
      /**
       * The same as [times]{@link module:ControlFlow.times} but runs only a single async operation at a time.
       *
       * @name timesSeries
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @see [async.times]{@link module:ControlFlow.times}
       * @category Control Flow
       * @param {number} n - The number of times to run the function.
       * @param {AsyncFunction} iteratee - The async function to call `n` times.
       * Invoked with the iteration index and a callback: (n, next).
       * @param {Function} callback - see {@link module:Collections.map}.
       * @returns {Promise} a promise, if no callback is provided
       */
      function timesSeries (n, iteratee, callback) {
          return timesLimit(n, 1, iteratee, callback)
      }
  
      /**
       * A relative of `reduce`.  Takes an Object or Array, and iterates over each
       * element in parallel, each step potentially mutating an `accumulator` value.
       * The type of the accumulator defaults to the type of collection passed in.
       *
       * @name transform
       * @static
       * @memberOf module:Collections
       * @method
       * @category Collection
       * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
       * @param {*} [accumulator] - The initial state of the transform.  If omitted,
       * it will default to an empty Object or Array, depending on the type of `coll`
       * @param {AsyncFunction} iteratee - A function applied to each item in the
       * collection that potentially modifies the accumulator.
       * Invoked with (accumulator, item, key, callback).
       * @param {Function} [callback] - A callback which is called after all the
       * `iteratee` functions have finished. Result is the transformed accumulator.
       * Invoked with (err, result).
       * @returns {Promise} a promise, if no callback provided
       * @example
       *
       * async.transform([1,2,3], function(acc, item, index, callback) {
       *     // pointless async:
       *     process.nextTick(function() {
       *         acc[index] = item * 2
       *         callback(null)
       *     });
       * }, function(err, result) {
       *     // result is now equal to [2, 4, 6]
       * });
       *
       * @example
       *
       * async.transform({a: 1, b: 2, c: 3}, function (obj, val, key, callback) {
       *     setImmediate(function () {
       *         obj[key] = val * 2;
       *         callback();
       *     })
       * }, function (err, result) {
       *     // result is equal to {a: 2, b: 4, c: 6}
       * })
       */
      function transform (coll, accumulator, iteratee, callback) {
          if (arguments.length <= 3 && typeof accumulator === 'function') {
              callback = iteratee;
              iteratee = accumulator;
              accumulator = Array.isArray(coll) ? [] : {};
          }
          callback = once(callback || promiseCallback());
          var _iteratee = wrapAsync(iteratee);
  
          eachOf$1(coll, (v, k, cb) => {
              _iteratee(accumulator, v, k, cb);
          }, err => callback(err, accumulator));
          return callback[PROMISE_SYMBOL]
      }
  
      /**
       * It runs each task in series but stops whenever any of the functions were
       * successful. If one of the tasks were successful, the `callback` will be
       * passed the result of the successful task. If all tasks fail, the callback
       * will be passed the error and result (if any) of the final attempt.
       *
       * @name tryEach
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @category Control Flow
       * @param {Array|Iterable|AsyncIterable|Object} tasks - A collection containing functions to
       * run, each function is passed a `callback(err, result)` it must call on
       * completion with an error `err` (which can be `null`) and an optional `result`
       * value.
       * @param {Function} [callback] - An optional callback which is called when one
       * of the tasks has succeeded, or all have failed. It receives the `err` and
       * `result` arguments of the last attempt at completing the `task`. Invoked with
       * (err, results).
       * @returns {Promise} a promise, if no callback is passed
       * @example
       * async.tryEach([
       *     function getDataFromFirstWebsite(callback) {
       *         // Try getting the data from the first website
       *         callback(err, data);
       *     },
       *     function getDataFromSecondWebsite(callback) {
       *         // First website failed,
       *         // Try getting the data from the backup website
       *         callback(err, data);
       *     }
       * ],
       * // optional callback
       * function(err, results) {
       *     Now do something with the data.
       * });
       *
       */
      function tryEach(tasks, callback) {
          var error = null;
          var result;
          return eachSeries$1(tasks, (task, taskCb) => {
              wrapAsync(task)((err, ...args) => {
                  if (err === false) return taskCb(err);
  
                  if (args.length < 2) {
                      [result] = args;
                  } else {
                      result = args;
                  }
                  error = err;
                  taskCb(err ? null : {});
              });
          }, () => callback(error, result));
      }
  
      var tryEach$1 = awaitify(tryEach);
  
      /**
       * Undoes a [memoize]{@link module:Utils.memoize}d function, reverting it to the original,
       * unmemoized form. Handy for testing.
       *
       * @name unmemoize
       * @static
       * @memberOf module:Utils
       * @method
       * @see [async.memoize]{@link module:Utils.memoize}
       * @category Util
       * @param {AsyncFunction} fn - the memoized function
       * @returns {AsyncFunction} a function that calls the original unmemoized function
       */
      function unmemoize(fn) {
          return (...args) => {
              return (fn.unmemoized || fn)(...args);
          };
      }
  
      /**
       * Repeatedly call `iteratee`, while `test` returns `true`. Calls `callback` when
       * stopped, or an error occurs.
       *
       * @name whilst
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @category Control Flow
       * @param {AsyncFunction} test - asynchronous truth test to perform before each
       * execution of `iteratee`. Invoked with ().
       * @param {AsyncFunction} iteratee - An async function which is called each time
       * `test` passes. Invoked with (callback).
       * @param {Function} [callback] - A callback which is called after the test
       * function has failed and repeated execution of `iteratee` has stopped. `callback`
       * will be passed an error and any arguments passed to the final `iteratee`'s
       * callback. Invoked with (err, [results]);
       * @returns {Promise} a promise, if no callback is passed
       * @example
       *
       * var count = 0;
       * async.whilst(
       *     function test(cb) { cb(null, count < 5;) },
       *     function iter(callback) {
       *         count++;
       *         setTimeout(function() {
       *             callback(null, count);
       *         }, 1000);
       *     },
       *     function (err, n) {
       *         // 5 seconds have passed, n = 5
       *     }
       * );
       */
      function whilst(test, iteratee, callback) {
          callback = onlyOnce(callback);
          var _fn = wrapAsync(iteratee);
          var _test = wrapAsync(test);
          var results = [];
  
          function next(err, ...rest) {
              if (err) return callback(err);
              results = rest;
              if (err === false) return;
              _test(check);
          }
  
          function check(err, truth) {
              if (err) return callback(err);
              if (err === false) return;
              if (!truth) return callback(null, ...results);
              _fn(next);
          }
  
          return _test(check);
      }
      var whilst$1 = awaitify(whilst, 3);
  
      /**
       * Repeatedly call `iteratee` until `test` returns `true`. Calls `callback` when
       * stopped, or an error occurs. `callback` will be passed an error and any
       * arguments passed to the final `iteratee`'s callback.
       *
       * The inverse of [whilst]{@link module:ControlFlow.whilst}.
       *
       * @name until
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @see [async.whilst]{@link module:ControlFlow.whilst}
       * @category Control Flow
       * @param {AsyncFunction} test - asynchronous truth test to perform before each
       * execution of `iteratee`. Invoked with (callback).
       * @param {AsyncFunction} iteratee - An async function which is called each time
       * `test` fails. Invoked with (callback).
       * @param {Function} [callback] - A callback which is called after the test
       * function has passed and repeated execution of `iteratee` has stopped. `callback`
       * will be passed an error and any arguments passed to the final `iteratee`'s
       * callback. Invoked with (err, [results]);
       * @returns {Promise} a promise, if a callback is not passed
       *
       * @example
       * const results = []
       * async.until(function iter(next) {
       *     fetchPage(url, (err, body) => {
       *         if (err) return next(err)
       *         results = results.concat(body.objects)
       *         next(err, body)
       *     })
       * }, function test(page, cb) {
       *     cb(null, page.next == null)
       * }, function done (err) {
       *     // all pages have been fetched
       * })
       */
      function until(test, iteratee, callback) {
          const _test = wrapAsync(test);
          return whilst$1((cb) => _test((err, truth) => cb (err, !truth)), iteratee, callback);
      }
  
      /**
       * Runs the `tasks` array of functions in series, each passing their results to
       * the next in the array. However, if any of the `tasks` pass an error to their
       * own callback, the next function is not executed, and the main `callback` is
       * immediately called with the error.
       *
       * @name waterfall
       * @static
       * @memberOf module:ControlFlow
       * @method
       * @category Control Flow
       * @param {Array} tasks - An array of [async functions]{@link AsyncFunction}
       * to run.
       * Each function should complete with any number of `result` values.
       * The `result` values will be passed as arguments, in order, to the next task.
       * @param {Function} [callback] - An optional callback to run once all the
       * functions have completed. This will be passed the results of the last task's
       * callback. Invoked with (err, [results]).
       * @returns undefined
       * @example
       *
       * async.waterfall([
       *     function(callback) {
       *         callback(null, 'one', 'two');
       *     },
       *     function(arg1, arg2, callback) {
       *         // arg1 now equals 'one' and arg2 now equals 'two'
       *         callback(null, 'three');
       *     },
       *     function(arg1, callback) {
       *         // arg1 now equals 'three'
       *         callback(null, 'done');
       *     }
       * ], function (err, result) {
       *     // result now equals 'done'
       * });
       *
       * // Or, with named functions:
       * async.waterfall([
       *     myFirstFunction,
       *     mySecondFunction,
       *     myLastFunction,
       * ], function (err, result) {
       *     // result now equals 'done'
       * });
       * function myFirstFunction(callback) {
       *     callback(null, 'one', 'two');
       * }
       * function mySecondFunction(arg1, arg2, callback) {
       *     // arg1 now equals 'one' and arg2 now equals 'two'
       *     callback(null, 'three');
       * }
       * function myLastFunction(arg1, callback) {
       *     // arg1 now equals 'three'
       *     callback(null, 'done');
       * }
       */
      function waterfall (tasks, callback) {
          callback = once(callback);
          if (!Array.isArray(tasks)) return callback(new Error('First argument to waterfall must be an array of functions'));
          if (!tasks.length) return callback();
          var taskIndex = 0;
  
          function nextTask(args) {
              var task = wrapAsync(tasks[taskIndex++]);
              task(...args, onlyOnce(next));
          }
  
          function next(err, ...args) {
              if (err === false) return
              if (err || taskIndex === tasks.length) {
                  return callback(err, ...args);
              }
              nextTask(args);
          }
  
          nextTask([]);
      }
  
      var waterfall$1 = awaitify(waterfall);
  
      /**
       * An "async function" in the context of Async is an asynchronous function with
       * a variable number of parameters, with the final parameter being a callback.
       * (`function (arg1, arg2, ..., callback) {}`)
       * The final callback is of the form `callback(err, results...)`, which must be
       * called once the function is completed.  The callback should be called with a
       * Error as its first argument to signal that an error occurred.
       * Otherwise, if no error occurred, it should be called with `null` as the first
       * argument, and any additional `result` arguments that may apply, to signal
       * successful completion.
       * The callback must be called exactly once, ideally on a later tick of the
       * JavaScript event loop.
       *
       * This type of function is also referred to as a "Node-style async function",
       * or a "continuation passing-style function" (CPS). Most of the methods of this
       * library are themselves CPS/Node-style async functions, or functions that
       * return CPS/Node-style async functions.
       *
       * Wherever we accept a Node-style async function, we also directly accept an
       * [ES2017 `async` function]{@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function}.
       * In this case, the `async` function will not be passed a final callback
       * argument, and any thrown error will be used as the `err` argument of the
       * implicit callback, and the return value will be used as the `result` value.
       * (i.e. a `rejected` of the returned Promise becomes the `err` callback
       * argument, and a `resolved` value becomes the `result`.)
       *
       * Note, due to JavaScript limitations, we can only detect native `async`
       * functions and not transpilied implementations.
       * Your environment must have `async`/`await` support for this to work.
       * (e.g. Node > v7.6, or a recent version of a modern browser).
       * If you are using `async` functions through a transpiler (e.g. Babel), you
       * must still wrap the function with [asyncify]{@link module:Utils.asyncify},
       * because the `async function` will be compiled to an ordinary function that
       * returns a promise.
       *
       * @typedef {Function} AsyncFunction
       * @static
       */
  
      var index = {
          apply,
          applyEach: applyEach$1,
          applyEachSeries,
          asyncify,
          auto,
          autoInject,
          cargo,
          cargoQueue: cargo$1,
          compose,
          concat: concat$1,
          concatLimit: concatLimit$1,
          concatSeries: concatSeries$1,
          constant,
          detect: detect$1,
          detectLimit: detectLimit$1,
          detectSeries: detectSeries$1,
          dir,
          doUntil,
          doWhilst: doWhilst$1,
          each,
          eachLimit: eachLimit$2,
          eachOf: eachOf$1,
          eachOfLimit: eachOfLimit$2,
          eachOfSeries: eachOfSeries$1,
          eachSeries: eachSeries$1,
          ensureAsync,
          every: every$1,
          everyLimit: everyLimit$1,
          everySeries: everySeries$1,
          filter: filter$1,
          filterLimit: filterLimit$1,
          filterSeries: filterSeries$1,
          forever: forever$1,
          groupBy,
          groupByLimit: groupByLimit$1,
          groupBySeries,
          log,
          map: map$1,
          mapLimit: mapLimit$1,
          mapSeries: mapSeries$1,
          mapValues,
          mapValuesLimit: mapValuesLimit$1,
          mapValuesSeries,
          memoize,
          nextTick,
          parallel,
          parallelLimit,
          priorityQueue,
          queue: queue$1,
          race: race$1,
          reduce: reduce$1,
          reduceRight,
          reflect,
          reflectAll,
          reject: reject$2,
          rejectLimit: rejectLimit$1,
          rejectSeries: rejectSeries$1,
          retry,
          retryable,
          seq,
          series,
          setImmediate: setImmediate$1,
          some: some$1,
          someLimit: someLimit$1,
          someSeries: someSeries$1,
          sortBy: sortBy$1,
          timeout,
          times,
          timesLimit,
          timesSeries,
          transform,
          tryEach: tryEach$1,
          unmemoize,
          until,
          waterfall: waterfall$1,
          whilst: whilst$1,
  
          // aliases
          all: every$1,
          allLimit: everyLimit$1,
          allSeries: everySeries$1,
          any: some$1,
          anyLimit: someLimit$1,
          anySeries: someSeries$1,
          find: detect$1,
          findLimit: detectLimit$1,
          findSeries: detectSeries$1,
          flatMap: concat$1,
          flatMapLimit: concatLimit$1,
          flatMapSeries: concatSeries$1,
          forEach: each,
          forEachSeries: eachSeries$1,
          forEachLimit: eachLimit$2,
          forEachOf: eachOf$1,
          forEachOfSeries: eachOfSeries$1,
          forEachOfLimit: eachOfLimit$2,
          inject: reduce$1,
          foldl: reduce$1,
          foldr: reduceRight,
          select: filter$1,
          selectLimit: filterLimit$1,
          selectSeries: filterSeries$1,
          wrapSync: asyncify,
          during: whilst$1,
          doDuring: doWhilst$1
      };
  
      exports.default = index;
      exports.apply = apply;
      exports.applyEach = applyEach$1;
      exports.applyEachSeries = applyEachSeries;
      exports.asyncify = asyncify;
      exports.auto = auto;
      exports.autoInject = autoInject;
      exports.cargo = cargo;
      exports.cargoQueue = cargo$1;
      exports.compose = compose;
      exports.concat = concat$1;
      exports.concatLimit = concatLimit$1;
      exports.concatSeries = concatSeries$1;
      exports.constant = constant;
      exports.detect = detect$1;
      exports.detectLimit = detectLimit$1;
      exports.detectSeries = detectSeries$1;
      exports.dir = dir;
      exports.doUntil = doUntil;
      exports.doWhilst = doWhilst$1;
      exports.each = each;
      exports.eachLimit = eachLimit$2;
      exports.eachOf = eachOf$1;
      exports.eachOfLimit = eachOfLimit$2;
      exports.eachOfSeries = eachOfSeries$1;
      exports.eachSeries = eachSeries$1;
      exports.ensureAsync = ensureAsync;
      exports.every = every$1;
      exports.everyLimit = everyLimit$1;
      exports.everySeries = everySeries$1;
      exports.filter = filter$1;
      exports.filterLimit = filterLimit$1;
      exports.filterSeries = filterSeries$1;
      exports.forever = forever$1;
      exports.groupBy = groupBy;
      exports.groupByLimit = groupByLimit$1;
      exports.groupBySeries = groupBySeries;
      exports.log = log;
      exports.map = map$1;
      exports.mapLimit = mapLimit$1;
      exports.mapSeries = mapSeries$1;
      exports.mapValues = mapValues;
      exports.mapValuesLimit = mapValuesLimit$1;
      exports.mapValuesSeries = mapValuesSeries;
      exports.memoize = memoize;
      exports.nextTick = nextTick;
      exports.parallel = parallel;
      exports.parallelLimit = parallelLimit;
      exports.priorityQueue = priorityQueue;
      exports.queue = queue$1;
      exports.race = race$1;
      exports.reduce = reduce$1;
      exports.reduceRight = reduceRight;
      exports.reflect = reflect;
      exports.reflectAll = reflectAll;
      exports.reject = reject$2;
      exports.rejectLimit = rejectLimit$1;
      exports.rejectSeries = rejectSeries$1;
      exports.retry = retry;
      exports.retryable = retryable;
      exports.seq = seq;
      exports.series = series;
      exports.setImmediate = setImmediate$1;
      exports.some = some$1;
      exports.someLimit = someLimit$1;
      exports.someSeries = someSeries$1;
      exports.sortBy = sortBy$1;
      exports.timeout = timeout;
      exports.times = times;
      exports.timesLimit = timesLimit;
      exports.timesSeries = timesSeries;
      exports.transform = transform;
      exports.tryEach = tryEach$1;
      exports.unmemoize = unmemoize;
      exports.until = until;
      exports.waterfall = waterfall$1;
      exports.whilst = whilst$1;
      exports.all = every$1;
      exports.allLimit = everyLimit$1;
      exports.allSeries = everySeries$1;
      exports.any = some$1;
      exports.anyLimit = someLimit$1;
      exports.anySeries = someSeries$1;
      exports.find = detect$1;
      exports.findLimit = detectLimit$1;
      exports.findSeries = detectSeries$1;
      exports.flatMap = concat$1;
      exports.flatMapLimit = concatLimit$1;
      exports.flatMapSeries = concatSeries$1;
      exports.forEach = each;
      exports.forEachSeries = eachSeries$1;
      exports.forEachLimit = eachLimit$2;
      exports.forEachOf = eachOf$1;
      exports.forEachOfSeries = eachOfSeries$1;
      exports.forEachOfLimit = eachOfLimit$2;
      exports.inject = reduce$1;
      exports.foldl = reduce$1;
      exports.foldr = reduceRight;
      exports.select = filter$1;
      exports.selectLimit = filterLimit$1;
      exports.selectSeries = filterSeries$1;
      exports.wrapSync = asyncify;
      exports.during = whilst$1;
      exports.doDuring = doWhilst$1;
  
      Object.defineProperty(exports, '__esModule', { value: true });
  
  })));
  