mqtt_client.dart: "Null check operator used on a null value" for authenticationManager in connect() method.

[stijn1989]

When an active connection to the MQTT server is lost. The _disconnect() method sets the authenticationManager to null.
When you call connect() again on the client, you get an exception "Null check operator used on a null value".
With this extra line of code, the authenticationManager has an object for sure.

Class MQTT {
  ....
  
  Future<MqttConnectionStatus?> connect() async {
    return client.connect(user, pass);
  }
  
  ...
}

...
FloatingActionButton(
  child: Icon(Icons.message),
  onPressed: () async {
      await mqtt.connect(); //<- here you get the exception when pressing the button when the MQTT is back online.
      mqtt.sub();
  }
)
....

[shamblett]

Yes good catch, client updated and re published at version 3.1.1