text: /* eslint guard-for-in:0 */
  
  var cryptoLib = require('crypto');
  var Buffer = require('buffer').Buffer;
  var AWS;
  
  /**
   * A set of utility methods for use with the AWS SDK.
   *
   * @!attribute abort
   *   Return this value from an iterator function {each} or {arrayEach}
   *   to break out of the iteration.
   *   @example Breaking out of an iterator function
   *     AWS.util.each({a: 1, b: 2, c: 3}, function(key, value) {
   *       if (key == 'b') return AWS.util.abort;
   *     });
   *   @see each
   *   @see arrayEach
   * @api private
   */
  var util = {
    engine: function engine() {
      if (util.isBrowser() && typeof navigator !== 'undefined') {
        return navigator.userAgent;
      } else {
        return process.platform + '/' + process.version;
      }
    },
  
    userAgent: function userAgent() {
      var name = util.isBrowser() ? 'js' : 'nodejs';
      var agent = 'aws-sdk-' + name + '/' + require('./core').VERSION;
      if (name === 'nodejs') agent += ' ' + util.engine();
      return agent;
    },
  
    isBrowser: function isBrowser() { return process && process.browser; },
    isNode: function isNode() { return !util.isBrowser(); },
    nodeRequire: function nodeRequire(module) {
      if (util.isNode()) return require(module);
    },
    multiRequire: function multiRequire(module1, module2) {
      return require(util.isNode() ? module1 : module2);
    },
  
    uriEscape: function uriEscape(string) {
      var output = encodeURIComponent(string);
      output = output.replace(/[^A-Za-z0-9_.~\-%]+/g, escape);
  
      // AWS percent-encodes some extra non-standard characters in a URI
      output = output.replace(/[*]/g, function(ch) {
        return '%' + ch.charCodeAt(0).toString(16).toUpperCase();
      });
  
      return output;
    },
  
    uriEscapePath: function uriEscapePath(string) {
      var parts = [];
      util.arrayEach(string.split('/'), function (part) {
        parts.push(util.uriEscape(part));
      });
      return parts.join('/');
    },
  
    urlParse: function urlParse(url) {
      return require('url').parse(url);
    },
  
    urlFormat: function urlFormat(url) {
      return require('url').format(url);
    },
  
    queryStringParse: function queryStringParse(qs) {
      return require('querystring').parse(qs);
    },
  
    queryParamsToString: function queryParamsToString(params) {
      var items = [];
      var escape = util.uriEscape;
      var sortedKeys = Object.keys(params).sort();
  
      util.arrayEach(sortedKeys, function(name) {
        var value = params[name];
        var ename = escape(name);
        var result = ename + '=';
        if (Array.isArray(value)) {
          var vals = [];
          util.arrayEach(value, function(item) { vals.push(escape(item)); });
          result = ename + '=' + vals.sort().join('&' + ename + '=');
        } else if (value !== undefined && value !== null) {
          result = ename + '=' + escape(value);
        }
        items.push(result);
      });
  
      return items.join('&');
    },
  
    readFileSync: function readFileSync(path) {
      if (util.isBrowser()) return null;
      return util.nodeRequire('fs').readFileSync(path, 'utf-8');
    },
  
    base64: {
  
      encode: function encode64(string) {
        return new Buffer(string).toString('base64');
      },
  
      decode: function decode64(string) {
        return new Buffer(string, 'base64');
      }
  
    },
  
    Buffer: Buffer,
  
    buffer: {
      toStream: function toStream(buffer) {
        if (!util.Buffer.isBuffer(buffer)) buffer = new util.Buffer(buffer);
  
        var readable = new (util.nodeRequire('stream').Readable)();
        var pos = 0;
        readable._read = function(size) {
          if (pos >= buffer.length) return readable.push(null);
  
          var end = pos + size;
          if (end > buffer.length) end = buffer.length;
          readable.push(buffer.slice(pos, end));
          pos = end;
        };
  
        return readable;
      },
  
      /**
       * Concatenates a list of Buffer objects.
       */
      concat: function(buffers) {
        var length = 0,
            offset = 0,
            buffer = null, i;
  
        for (i = 0; i < buffers.length; i++) {
          length += buffers[i].length;
        }
  
        buffer = new Buffer(length);
  
        for (i = 0; i < buffers.length; i++) {
          buffers[i].copy(buffer, offset);
          offset += buffers[i].length;
        }
  
        return buffer;
      }
    },
  
    string: {
      byteLength: function byteLength(string) {
        if (string === null || string === undefined) return 0;
        if (typeof string === 'string') string = new Buffer(string);
  
        if (typeof string.byteLength === 'number') {
          return string.byteLength;
        } else if (typeof string.length === 'number') {
          return string.length;
        } else if (typeof string.size === 'number') {
          return string.size;
        } else if (typeof string.path === 'string') {
          return util.nodeRequire('fs').lstatSync(string.path).size;
        } else {
          throw util.error(new Error('Cannot determine length of ' + string),
            { object: string });
        }
      },
  
      upperFirst: function upperFirst(string) {
        return string[0].toUpperCase() + string.substr(1);
      },
  
      lowerFirst: function lowerFirst(string) {
        return string[0].toLowerCase() + string.substr(1);
      }
    },
  
    ini: {
      parse: function string(ini) {
        var currentSection, map = {};
        util.arrayEach(ini.split(/\r?\n/), function(line) {
          line = line.split(/(^|\s)[;#]/)[0]; // remove comments
          var section = line.match(/^\s*\[([^\[\]]+)\]\s*$/);
          if (section) {
            currentSection = section[1];
          } else if (currentSection) {
            var item = line.match(/^\s*(.+?)\s*=\s*(.+?)\s*$/);
            if (item) {
              map[currentSection] = map[currentSection] || {};
              map[currentSection][item[1]] = item[2];
            }
          }
        });
  
        return map;
      }
    },
  
    fn: {
      noop: function() {},
  
      /**
       * Turn a synchronous function into as "async" function by making it call
       * a callback. The underlying function is called with all but the last argument,
       * which is treated as the callback. The callback is passed passed a first argument
       * of null on success to mimick standard node callbacks.
       */
      makeAsync: function makeAsync(fn, expectedArgs) {
        if (expectedArgs && expectedArgs <= fn.length) {
          return fn;
        }
  
        return function() {
          var args = Array.prototype.slice.call(arguments, 0);
          var callback = args.pop();
          var result = fn.apply(null, args);
          callback(result);
        };
      }
    },
  
    /**
     * Date and time utility functions.
     */
    date: {
  
      /**
       * @return [Date] the current JavaScript date object. Since all
       *   AWS services rely on this date object, you can override
       *   this function to provide a special time value to AWS service
       *   requests.
       */
      getDate: function getDate() {
        if (!AWS) AWS = require('./core');
        if (AWS.config.systemClockOffset) { // use offset when non-zero
          return new Date(new Date().getTime() + AWS.config.systemClockOffset);
        } else {
          return new Date();
        }
      },
  
      /**
       * @return [String] the date in ISO-8601 format
       */
      iso8601: function iso8601(date) {
        if (date === undefined) { date = util.date.getDate(); }
        return date.toISOString().replace(/\.\d{3}Z$/, 'Z');
      },
  
      /**
       * @return [String] the date in RFC 822 format
       */
      rfc822: function rfc822(date) {
        if (date === undefined) { date = util.date.getDate(); }
        return date.toUTCString();
      },
  
      /**
       * @return [Integer] the UNIX timestamp value for the current time
       */
      unixTimestamp: function unixTimestamp(date) {
        if (date === undefined) { date = util.date.getDate(); }
        return date.getTime() / 1000;
      },
  
      /**
       * @param [String,number,Date] date
       * @return [Date]
       */
      from: function format(date) {
        if (typeof date === 'number') {
          return new Date(date * 1000); // unix timestamp
        } else {
          return new Date(date);
        }
      },
  
      /**
       * Given a Date or date-like value, this function formats the
       * date into a string of the requested value.
       * @param [String,number,Date] date
       * @param [String] formatter Valid formats are:
       #   * 'iso8601'
       #   * 'rfc822'
       #   * 'unixTimestamp'
       * @return [String]
       */
      format: function format(date, formatter) {
        if (!formatter) formatter = 'iso8601';
        return util.date[formatter](util.date.from(date));
      },
  
      parseTimestamp: function parseTimestamp(value) {
        if (typeof value === 'number') { // unix timestamp (number)
          return new Date(value * 1000);
        } else if (value.match(/^\d+$/)) { // unix timestamp
          return new Date(value * 1000);
        } else if (value.match(/^\d{4}/)) { // iso8601
          return new Date(value);
        } else if (value.match(/^\w{3},/)) { // rfc822
          return new Date(value);
        } else {
          throw util.error(
            new Error('unhandled timestamp format: ' + value),
            {code: 'TimestampParserError'});
        }
      }
  
    },
  
    crypto: {
      crc32Table: [
       0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419,
       0x706AF48F, 0xE963A535, 0x9E6495A3, 0x0EDB8832, 0x79DCB8A4,
       0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07,
       0x90BF1D91, 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
       0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 0x136C9856,
       0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9,
       0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4,
       0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
       0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3,
       0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 0x26D930AC, 0x51DE003A,
       0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599,
       0xB8BDA50F, 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
       0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 0x76DC4190,
       0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F,
       0x9FBFE4A5, 0xE8B8D433, 0x7807C9A2, 0x0F00F934, 0x9609A88E,
       0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
       0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED,
       0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950,
       0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3,
       0xFBD44C65, 0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
       0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A,
       0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5,
       0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C, 0x270241AA, 0xBE0B1010,
       0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
       0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17,
       0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6,
       0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615,
       0x73DC1683, 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
       0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1, 0xF00F9344,
       0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB,
       0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A,
       0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
       0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1,
       0xA6BC5767, 0x3FB506DD, 0x48B2364B, 0xD80D2BDA, 0xAF0A1B4C,
       0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF,
       0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
       0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, 0xC5BA3BBE,
       0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31,
       0x2CD99E8B, 0x5BDEAE1D, 0x9B64C2B0, 0xEC63F226, 0x756AA39C,
       0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
       0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B,
       0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242,
       0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1,
       0x18B74777, 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
       0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45, 0xA00AE278,
       0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7,
       0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66,
       0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
       0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605,
       0xCDD70693, 0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8,
       0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B,
       0x2D02EF8D],
  
      crc32: function crc32(data) {
        var tbl = util.crypto.crc32Table;
        var crc = 0 ^ -1;
  
        if (typeof data === 'string') {
          data = new Buffer(data);
        }
  
        for (var i = 0; i < data.length; i++) {
          var code = data.readUInt8(i);
          crc = (crc >>> 8) ^ tbl[(crc ^ code) & 0xFF];
        }
        return (crc ^ -1) >>> 0;
      },
  
      hmac: function hmac(key, string, digest, fn) {
        if (!digest) digest = 'binary';
        if (digest === 'buffer') { digest = undefined; }
        if (!fn) fn = 'sha256';
        if (typeof string === 'string') string = new Buffer(string);
        return cryptoLib.createHmac(fn, key).update(string).digest(digest);
      },
  
      md5: function md5(data, digest, callback) {
        return util.crypto.hash('md5', data, digest, callback);
      },
  
      sha256: function sha256(data, digest, callback) {
        return util.crypto.hash('sha256', data, digest, callback);
      },
  
      hash: function(algorithm, data, digest, callback) {
        var hash = util.crypto.createHash(algorithm);
        if (!digest) { digest = 'binary'; }
        if (digest === 'buffer') { digest = undefined; }
        if (typeof data === 'string') data = new Buffer(data);
        var sliceFn = util.arraySliceFn(data);
        var isBuffer = Buffer.isBuffer(data);
        //Identifying objects with an ArrayBuffer as buffers
        if (util.isBrowser() && typeof ArrayBuffer !== 'undefined' && data && data.buffer instanceof ArrayBuffer) isBuffer = true;
  
        if (callback && typeof data === 'object' &&
            typeof data.on === 'function' && !isBuffer) {
          data.on('data', function(chunk) { hash.update(chunk); });
          data.on('error', function(err) { callback(err); });
          data.on('end', function() { callback(null, hash.digest(digest)); });
        } else if (callback && sliceFn && !isBuffer &&
                   typeof FileReader !== 'undefined') {
          // this might be a File/Blob
          var index = 0, size = 1024 * 512;
          var reader = new FileReader();
          reader.onerror = function() {
            callback(new Error('Failed to read data.'));
          };
          reader.onload = function() {
            var buf = new Buffer(new Uint8Array(reader.result));
            hash.update(buf);
            index += buf.length;
            reader._continueReading();
          };
          reader._continueReading = function() {
            if (index >= data.size) {
              callback(null, hash.digest(digest));
              return;
            }
  
            var back = index + size;
            if (back > data.size) back = data.size;
            reader.readAsArrayBuffer(sliceFn.call(data, index, back));
          };
  
          reader._continueReading();
        } else {
          if (util.isBrowser() && typeof data === 'object' && !isBuffer) {
            data = new Buffer(new Uint8Array(data));
          }
          var out = hash.update(data).digest(digest);
          if (callback) callback(null, out);
          return out;
        }
      },
  
      toHex: function toHex(data) {
        var out = [];
        for (var i = 0; i < data.length; i++) {
          out.push(('0' + data.charCodeAt(i).toString(16)).substr(-2, 2));
        }
        return out.join('');
      },
  
      createHash: function createHash(algorithm) {
        return cryptoLib.createHash(algorithm);
      }
  
    },
  
    /** @!ignore */
  
    /* Abort constant */
    abort: {},
  
    each: function each(object, iterFunction) {
      for (var key in object) {
        if (Object.prototype.hasOwnProperty.call(object, key)) {
          var ret = iterFunction.call(this, key, object[key]);
          if (ret === util.abort) break;
        }
      }
    },
  
    arrayEach: function arrayEach(array, iterFunction) {
      for (var idx in array) {
        if (Object.prototype.hasOwnProperty.call(array, idx)) {
          var ret = iterFunction.call(this, array[idx], parseInt(idx, 10));
          if (ret === util.abort) break;
        }
      }
    },
  
    update: function update(obj1, obj2) {
      util.each(obj2, function iterator(key, item) {
        obj1[key] = item;
      });
      return obj1;
    },
  
    merge: function merge(obj1, obj2) {
      return util.update(util.copy(obj1), obj2);
    },
  
    copy: function copy(object) {
      if (object === null || object === undefined) return object;
      var dupe = {};
      // jshint forin:false
      for (var key in object) {
        dupe[key] = object[key];
      }
      return dupe;
    },
  
    isEmpty: function isEmpty(obj) {
      for (var prop in obj) {
        if (Object.prototype.hasOwnProperty.call(obj, prop)) {
          return false;
        }
      }
      return true;
    },
  
    arraySliceFn: function arraySliceFn(obj) {
      var fn = obj.slice || obj.webkitSlice || obj.mozSlice;
      return typeof fn === 'function' ? fn : null;
    },
  
    isType: function isType(obj, type) {
      // handle cross-"frame" objects
      if (typeof type === 'function') type = util.typeName(type);
      return Object.prototype.toString.call(obj) === '[object ' + type + ']';
    },
  
    typeName: function typeName(type) {
      if (Object.prototype.hasOwnProperty.call(type, 'name')) return type.name;
      var str = type.toString();
      var match = str.match(/^\s*function (.+)\(/);
      return match ? match[1] : str;
    },
  
    error: function error(err, options) {
      var originalError = null;
      if (typeof err.message === 'string' && err.message !== '') {
        if (typeof options === 'string' || (options && options.message)) {
          originalError = util.copy(err);
          originalError.message = err.message;
        }
      }
      err.message = err.message || null;
  
      if (typeof options === 'string') {
        err.message = options;
      } else if (typeof options === 'object' && options !== null) {
        util.update(err, options);
        if (options.message)
          err.message = options.message;
        if (options.code || options.name)
          err.code = options.code || options.name;
        if (options.stack)
          err.stack = options.stack;
      }
  
      if (typeof Object.defineProperty === 'function') {
        Object.defineProperty(err, 'name', {writable: true, enumerable: false});
        Object.defineProperty(err, 'message', {enumerable: true});
      }
  
      err.name = options && options.name || err.name || err.code || 'Error';
      err.time = new Date();
  
      if (originalError) err.originalError = originalError;
  
      return err;
    },
  
    /**
     * @api private
     */
    inherit: function inherit(klass, features) {
      var newObject = null;
      if (features === undefined) {
        features = klass;
        klass = Object;
        newObject = {};
      } else {
        var ctor = function ConstructorWrapper() {};
        ctor.prototype = klass.prototype;
        newObject = new ctor();
      }
  
      // constructor not supplied, create pass-through ctor
      if (features.constructor === Object) {
        features.constructor = function() {
          if (klass !== Object) {
            return klass.apply(this, arguments);
          }
        };
      }
  
      features.constructor.prototype = newObject;
      util.update(features.constructor.prototype, features);
      features.constructor.__super__ = klass;
      return features.constructor;
    },
  
    /**
     * @api private
     */
    mixin: function mixin() {
      var klass = arguments[0];
      for (var i = 1; i < arguments.length; i++) {
        // jshint forin:false
        for (var prop in arguments[i].prototype) {
          var fn = arguments[i].prototype[prop];
          if (prop !== 'constructor') {
            klass.prototype[prop] = fn;
          }
        }
      }
      return klass;
    },
  
    /**
     * @api private
     */
    hideProperties: function hideProperties(obj, props) {
      if (typeof Object.defineProperty !== 'function') return;
  
      util.arrayEach(props, function (key) {
        Object.defineProperty(obj, key, {
          enumerable: false, writable: true, configurable: true });
      });
    },
  
    /**
     * @api private
     */
    property: function property(obj, name, value, enumerable, isValue) {
      var opts = {
        configurable: true,
        enumerable: enumerable !== undefined ? enumerable : true
      };
      if (typeof value === 'function' && !isValue) {
        opts.get = value;
      }
      else {
        opts.value = value; opts.writable = true;
      }
  
      Object.defineProperty(obj, name, opts);
    },
  
    /**
     * @api private
     */
    memoizedProperty: function memoizedProperty(obj, name, get, enumerable) {
      var cachedValue = null;
  
      // build enumerable attribute for each value with lazy accessor.
      util.property(obj, name, function() {
        if (cachedValue === null) {
          cachedValue = get();
        }
        return cachedValue;
      }, enumerable);
    },
  
    /**
     * TODO Remove in major version revision
     * This backfill populates response data without the
     * top-level payload name.
     *
     * @api private
     */
    hoistPayloadMember: function hoistPayloadMember(resp) {
      var req = resp.request;
      var operation = req.operation;
      var output = req.service.api.operations[operation].output;
      if (output.payload) {
        var payloadMember = output.members[output.payload];
        var responsePayload = resp.data[output.payload];
        if (payloadMember.type === 'structure') {
          util.each(responsePayload, function(key, value) {
            util.property(resp.data, key, value, false);
          });
        }
      }
    },
  
    /**
     * Compute SHA-256 checksums of streams
     *
     * @api private
     */
    computeSha256: function computeSha256(body, done) {
      if (util.isNode()) {
        var Stream = util.nodeRequire('stream').Stream;
        var fs = util.nodeRequire('fs');
        if (body instanceof Stream) {
          if (typeof body.path === 'string') { // assume file object
            var settings = {};
            if (typeof body.start === 'number') {
              settings.start = body.start;
            }
            if (typeof body.end === 'number') {
              settings.end = body.end;
            }
            body = fs.createReadStream(body.path, settings);
          } else { // TODO support other stream types
            return done(new Error('Non-file stream objects are ' +
                                  'not supported with SigV4'));
          }
        }
      }
  
      util.crypto.sha256(body, 'hex', function(err, sha) {
        if (err) done(err);
        else done(null, sha);
      });
    },
  
    /**
     * @api private
     */
    isClockSkewed: function isClockSkewed(serverTime) {
      if (serverTime) {
        util.property(AWS.config, 'isClockSkewed',
          Math.abs(new Date().getTime() - serverTime) >= 300000, false);
        return AWS.config.isClockSkewed;
      }
    },
  
    applyClockOffset: function applyClockOffset(serverTime) {
      if (serverTime)
        AWS.config.systemClockOffset = serverTime - new Date().getTime();
    },
  
    /**
     * @api private
     */
    extractRequestId: function extractRequestId(resp) {
      var requestId = resp.httpResponse.headers['x-amz-request-id'] ||
                       resp.httpResponse.headers['x-amzn-requestid'];
  
      if (!requestId && resp.data && resp.data.ResponseMetadata) {
        requestId = resp.data.ResponseMetadata.RequestId;
      }
  
      if (requestId) {
        resp.requestId = requestId;
      }
  
      if (resp.error) {
        resp.error.requestId = requestId;
      }
    },
  
    /**
     * @api private
     */
    addPromisesToRequests: function addPromisesToRequests(constructor, PromiseDependency) {
      PromiseDependency = PromiseDependency || null;
      if (!PromiseDependency && typeof Promise !== 'undefined') {
        PromiseDependency = Promise;
      }
      if (typeof PromiseDependency !== 'function') {
        delete constructor.prototype.promise;
        return;
      }
      constructor.prototype.promise = function promise() {
        var self = this;
        return new PromiseDependency(function(resolve, reject) {
          self.on('complete', function(resp) {
            if (resp.error) {
              reject(resp.error);
            } else {
              resolve(resp.data);
            }
          });
          self.runTo();
        });
      }
    },
  
    /**
     * @api private
     */
    isDualstackAvailable: function isDualstackAvailable(service) {
      if (!service) return false;
      var metadata = require('../apis/metadata.json');
      if (typeof service !== 'string') service = service.serviceIdentifier;
      if (typeof service !== 'string' || !metadata.hasOwnProperty(service)) return false;
      return !!metadata[service].dualstackAvailable;
    }
  
  };
  
  module.exports = util;
  