anchor.diff:     * Called when underlying socket received a message.
      */
     void _onMessageHandler(sockjs.MessageEvent event) {
  -    _logger.info("Message " + event.toString());
  +    _logger.info("MessageHandler " + event.type);
   
       var json = JSON.decode(event.data);
       var body = json['body'];
  
positive.code:    * Called when underlying socket is opened.
     */
    void _onOpenHandler(sockjsevent.Event event) {
      _logger.info('Open ' + event.toString());
      _state = OPEN;
      _heartbeatTimer = new Timer.periodic(HEARTBEAT_INTERVAL, ping);
      ping(_heartbeatTimer);
  
negative.code:    * Internal method to do the sending.
     */
    void _doSend(String type, String address, var message, [void replyCallback(BusMessageEvent)]) {
      if (state != OPEN) {
        throw new StateError("Connection not OPEN: '" + state + "'");
      }
      
      var envelope = {
          'type' : type,
          'address' : address,
          'body' : message
      };
      if (_sessionID != null) {
        envelope['body']['sessionID'] = _sessionID;
      }
      if (replyCallback != null) {
        var replyAddress = uuid.v4();
  