requestMtu method
Request to change the MTU Size Throws error if request did not complete successfully
Implementation
Future<void> requestMtu(int desiredMtu) async {
var request = protos.MtuSizeRequest.create()
..remoteId = id.toString()
..mtu = desiredMtu;
return FlutterBlue.instance._channel
.invokeMethod('requestMtu', request.writeToBuffer());
}