listen method
Implementation
void listen(Function(List<ReceivedMessage>) callback) {
mqttClient?.updates?.listen((List<MqttReceivedMessage<MqttMessage>> c) {
if (c.isEmpty) return;
var receivedMessages = c.map((e) {
var topic = e.topic;
var payload = e.payload;
var recMess = payload as MqttPublishMessage;
var message = utf8.decode(recMess.payload.message);
return ReceivedMessage(topic, message);
}).toList();
callback(receivedMessages);
});
}