anchor.diff:    }
   
     void _handleErr() {
  +    this._heartbeatTimer.cancel();
  +
       switch (this._socket.closeCode) {
         case 1005:
           return;
  
positive.code:   }
  
    void _heartbeat() {
      this.send("HEARTBEAT", _sequence);
    }
  
  
negative.code:             "seq": this._sequence
            });
          }
  
          this._heartbeatTimer = new Timer.periodic(
              new Duration(milliseconds: json['d']['heartbeat_interval']),
              (Timer t) => this._heartbeat());
          break;
  
        case _OPCodes.invalidSession:
  