[firebase_messaging] communicate with backgroundHandler

[Topup3]

Hi, how could we communicate with a process which is started in backgroundHandler function.

For example, I'm trying to run incall plugin (https://pub.dev/packages/flutter_incall) in backgroundHandler function, when app get a notification, phone start ringing but I can not stop it because of backgroundHandler working as Isolate thread.

Code Example:

IncallManager incallManager = new IncallManager();

Future<void> _firebaseMessagingBackgroundHandler(RemoteMessage message) async {
    await Firebase.initializeApp();

    flutterLocalNotificationsPlugin.show(/* notification details*/);

    incallManager.setKeepScreenOn(true);
    incallManager.startRingtone(RingtoneUriType.BUNDLE, 'default', 30,);
}

incallManager.stopRingtone(); command not working when we run it after user click notification and open the app.