text: var AwaitValue = require("./AwaitValue");
  
  function AsyncGenerator(gen) {
    var front, back;
  
    function send(key, arg) {
      return new Promise(function (resolve, reject) {
        var request = {
          key: key,
          arg: arg,
          resolve: resolve,
          reject: reject,
          next: null
        };
  
        if (back) {
          back = back.next = request;
        } else {
          front = back = request;
          resume(key, arg);
        }
      });
    }
  
    function resume(key, arg) {
      try {
        var result = gen[key](arg);
        var value = result.value;
        var wrappedAwait = value instanceof AwaitValue;
        Promise.resolve(wrappedAwait ? value.wrapped : value).then(function (arg) {
          if (wrappedAwait) {
            resume("next", arg);
            return;
          }
  
          settle(result.done ? "return" : "normal", arg);
        }, function (err) {
          resume("throw", err);
        });
      } catch (err) {
        settle("throw", err);
      }
    }
  
    function settle(type, value) {
      switch (type) {
        case "return":
          front.resolve({
            value: value,
            done: true
          });
          break;
  
        case "throw":
          front.reject(value);
          break;
  
        default:
          front.resolve({
            value: value,
            done: false
          });
          break;
      }
  
      front = front.next;
  
      if (front) {
        resume(front.key, front.arg);
      } else {
        back = null;
      }
    }
  
    this._invoke = send;
  
    if (typeof gen["return"] !== "function") {
      this["return"] = undefined;
    }
  }
  
  if (typeof Symbol === "function" && Symbol.asyncIterator) {
    AsyncGenerator.prototype[Symbol.asyncIterator] = function () {
      return this;
    };
  }
  
  AsyncGenerator.prototype.next = function (arg) {
    return this._invoke("next", arg);
  };
  
  AsyncGenerator.prototype["throw"] = function (arg) {
    return this._invoke("throw", arg);
  };
  
  AsyncGenerator.prototype["return"] = function (arg) {
    return this._invoke("return", arg);
  };
  
  module.exports = AsyncGenerator;