sendMsg function
Send a message with the given message ID and message payload. Returns a boolean that specifies if the command was successful.
Implementation
bool sendMsg(int msgID, String payload) {
  // Ensures that the RCON socket exists.
  if (rconSck == null) {
    return false;
  }
  // Message length is the payload length + 10 to account
  // for the headers and suffix.
  int msgLen = 10 + payload.length;
  // Creates the full RCON message.
  Uint8List fullMsg = cM(msgLen, msgID, payload);
  // Add the RCON message to the socket stream.
  rconSck!.add(fullMsg);
  print("mc_rcon: sent payload ($fullMsg) on socket");
  return true;
}