publish method
void
publish(})
Implementation
void publish(String topic, String message,
{retain = false, qos = CommunicatorQos.atLeastOnce}) {
if (communicator == null) {
_log.warning("Can't publish() before connect()");
return;
}
_log.fine("publishing to $topic: $message (retain: $retain, qos: $qos)");
communicator!.publish(topic, message, qos: qos, retain: retain);
}