sendCmd method
andBoost
will flag the heartbeat to poll Onyx more frequently
Implementation
Future<OnyxMessage?> sendCmd(String cmd, [bool andBoost = false]) async {
// never send an empty command
// all other commands will receive a response
if (cmd.trim().isEmpty) return null;
// wait until the previous command is completed if there is one
await _completer?.future;
if (!connected) await connect();
_dbg('${DateTime.now().toIso8601String()} ONYX SEND: $cmd');
_socket?.write(cmd + '\r\n');
if (andBoost) boostHeartbeat(6);
return _expectResponse(timeoutMsg: 'Sending "$cmd", command timed out...');
}