constructor(options: HttpChannelOptions) {
   super(options);
   this._sequence = 1;
   this._maxPostSize = options.maxPostSize || 100000;
   this._messageBuffer = [];
   this._lastRequest = Task.resolve();
 }

 const request = spy((path: string, data: any) => {
   if (requestHandler) {
     return requestHandler(path, data);
   }
   const result = requestData && requestData[path];
   return Task.resolve(result);
 });

  protected _handleError(error: Error) {
    // Make the _ready task a reject to reject future _sendData calls
    this._ready = Task.reject(error);

    // Reject any open sends
    Object.keys(this._sendQueue)
      .filter(id => this._sendQueue[id] != null)
      .forEach(id => {
        this._sendQueue[id]!.reject(error);
        this._sendQueue[id] = undefined;
      });
  }

 download(forceDownload = false): CancellablePromise<void> {
   if (!forceDownload && this.isDownloaded) {
     return Task.resolve();
   }
   return new Task((resolve, reject) => {
     exec(
       `npm install --no-save cbt_tunnels@${this.cbtVersion}`,
       (error, _stdout, stderr) => {
         if (error) {
           console.error(stderr);
           reject(error);
         } else {
           resolve();
         }
       }
     );
   });
 }

 json: () => Task.resolve(responses)

 sendJobState(): CancellablePromise<void> {
   return Task.resolve();
 }

 start(): CancellablePromise<void> {
   this._state = 'running';
   return Task.resolve();
 }

 download(): CancellablePromise<void> {
   return Task.resolve();
 }

 const request = spy((path: string) => {
   const data = requestData && requestData[path];
   return Task.resolve(new MockResponse(data));
 });

 text() {
   return Task.resolve(this.data);
 }