anchor.diff:  
     /// Read data send from the serial port
     Stream<List<int>> get onRead {
  -    StreamController<String> controller = new StreamController();
  +    StreamController<int> controller = new StreamController();
       _onReadControllers.add(controller);
       return controller.stream;
     }
  
positive.code:   int get fd => _ttyFd;
  
    /// Close the connection.
    Future<bool> close(){
      _checkOpen();
      final completer = new Completer<bool>();
      final replyPort = new ReceivePort();
  
negative.code:   }
  
    /// Write bytes
    Future write(List<int> bytes){
      final writes = bytes.map((byte) => _writeOneByte(byte));
      return Future.wait(writes, eagerError: true).then((_) => true);
    }
  
    Future _writeOneByte(int byte){
      _checkOpen();
      final completer = new Completer<bool>();
      final replyPort = new ReceivePort();
      _servicePort.send([replyPort.sendPort, _WRITE_BYTE_METHOD, _ttyFd, byte]);
      replyPort.first.then((result) {
        if (result[0] == null) {
          completer.complete();
        } else {
          completer.completeError("Cannot write in $portname : ${result[0]}");
        }
  