anchor.diff:     */
     final Queue<Map> _requestQueue = new Queue<Map>();
   
  +  /**
  +   * Maps [Request] names to their future responses.
  +   */
  +  final Map<int, Completer> _responseMap = new Map<int, Completer>();
  +
  +  /**
  +   * Counts sent requests. Serves as unique ID for new requests.
  +   */
  +  int requestCount = 0;
  +
  +  List<PackedRequest> _prepareRequest() {
  +    var request_list = [];
  +    while (!_requestQueue.isEmpty) {
  +      var map = _requestQueue.removeFirst();
  +      var clientRequest = map['createRequest'](); // create the request
  +      request_list.add(new PackedRequest(requestCount, clientRequest));
  +      _responseMap[requestCount++] = map['completer'];
  +    }
  +    return request_list;
  +  }
  +
  +  void _handleResponse(List responses) {
  +    for (var responseMap in responses) {
  +      var id = responseMap['id'];
  +      var response = responseMap['response'];
  +      if (_responseMap.containsKey(id)) {
  +        _responseMap[id].complete(response);
  +        _responseMap.remove(id);
  +      }
  +    }
  +    _responseMap.forEach((id, request) {
  +      throw new Exception("Request $id was not answered!");
  +    });
  +  }
  +
     void performRequest();
   
     /**
  
positive.code:   /**
     * Creates a new [Connection] with specified [HttpRequestFactory]
     */
    HttpConnection.config(this._factory, this._url, this._delayBetweenRequests);
  
    /**
     * Maps [Request] names to their future responses.
     */
    final Map<int, Completer> _responseMap = new Map<int, Completer>();
  
    /**
     * Counts sent requests. Serves as unique ID for new requests.
     */
    int requestCount = 0;
  
    /**
     * Begins performing HttpRequest. Is not launched if another request is
     * already running or the request Queue is empty. Sets [_isRunning] as true
  
negative.code:    * RequestFactory is a function like HttpRequest.request() that returns
     * [Future<HttpRequest>].
     */
    final HttpRequestFactory _sendHttpRequest;
  
    /**
     * The URL where to perform requests.
  