Flutter: How to configure audio_session to duck others

I need to play audio without interrupting an existing playlist. My goal is to play an audio over the current audio service that is going on the phone, ideally I would like to duck the audio and play my stream over it. Pretty much like GPS services do while driving (Waze, Google maps).

Steps:

1. Install dependencies
2. Create initAudioService() function
3. Create an AudioSession instance
4. Configure your AudioSession instance as in the example
5. Initialize your AudioService as in the example
6. Call initAudioService() from main before runApp

Dependencies:

• audio_service: ^0.18.0;
• audio_session: ^0.1.6+1

Example:

    import 'package:audio_service/audio_service.dart';
    import 'package:audio_session/audio_session.dart';
    import 'audio_player_service.dart';
    
    Future initAudioService() async {
      //audio_session INSTANCE
      final session = await AudioSession.instance;
      //audio_session DUCK OTHERS CONFIGURATION
      await session.configure(const AudioSessionConfiguration(
        avAudioSessionCategory: AVAudioSessionCategory.playback,
        avAudioSessionCategoryOptions: AVAudioSessionCategoryOptions.duckOthers,
        avAudioSessionMode: AVAudioSessionMode.defaultMode,
        avAudioSessionRouteSharingPolicy:
            AVAudioSessionRouteSharingPolicy.defaultPolicy,
        avAudioSessionSetActiveOptions: AVAudioSessionSetActiveOptions.none,
        androidAudioAttributes: AndroidAudioAttributes(
          contentType: AndroidAudioContentType.music,
          flags: AndroidAudioFlags.none,
          usage: AndroidAudioUsage.media,
        ),
        androidAudioFocusGainType: AndroidAudioFocusGainType.gainTransientMayDuck,
        androidWillPauseWhenDucked: true,
      ));
    //INITIALIZE audio_service
      return await AudioService.init(
        builder: () => AudioPlayerService(),
        config: const AudioServiceConfig(
          androidNotificationChannelId: 'com.YOUR_COMPANY.YOUR_APP_NAME.audio',
          androidNotificationChannelName: 'Audio Service Demo',
          androidNotificationOngoing: true,
          androidStopForegroundOnPause: true,
        ),
      );
    }
    
    //MAIN
    void main() async {
      await initAudioService();
      runApp(const MaterialApp(home: MyApp()));
    }