code: def send_msg(self, msg, wait_nak=True, wait_timeout=WAIT_TIMEOUT):
          
          msg_info = MessageInfo(msg=msg, wait_nak=wait_nak,
                                 wait_timeout=wait_timeout)
          _LOGGER.debug("Queueing msg: %s", msg)
          self._send_queue.put_nowait(msg_info)
docs: Place a message on the send queue for sending.
  
          Message are sent in the order they are placed in the queue.