How do you know if sending a message was successful about mqtt_client HOT 3 CLOSED

If you use a high QOS level such as 1 or 2 the client will handle re transmission for you, see here. This however is transparent to you unless you listen to the published message stream, from the client api -

 /// Published message stream. A publish message is added to this
  /// stream on completion of the message publishing protocol for a Qos level.
  /// Attach listeners only after connect has been called.
  Stream<MqttPublishMessage>? get published =>
      publishingManager != null ? publishingManager!.published.stream : null;

from mqtt_client.

If you use a high QOS level such as 1 or 2 the client will handle re transmission for you, see here. This however is transparent to you unless you listen to the published message stream, from the client api -

 /// Published message stream. A publish message is added to this
  /// stream on completion of the message publishing protocol for a Qos level.
  /// Attach listeners only after connect has been called.
  Stream<MqttPublishMessage>? get published =>
      publishingManager != null ? publishingManager!.published.stream : null;

Hello, I'm a newbie. Isn't there a method to listen specifically for successful delivery? Similar to Bluetooth write success callback. Any sample code? Thank you very much

from mqtt_client.

All the client does is to place successfully sent messages on the publish stream. How you ascertain your messages are being delivered to the broker as you expect is up to you, you could not send the next message until the last one you have sent appears on the publish queue, you could place a token in the payload say and keep track that way, there are other ways. The client shouldn't constrain you in how you do this.

Listening on the publish stream is like a 'write success callback' as you say above.

from mqtt_client.