anchor.diff:    }
   
     factory AssetsAudioPlayer.newPlayer() => _getOrCreate(id: uuid.v4());
  +
  +  final AudioPlayerHandler audioPlayerHandler;
   
     /// empty constructor now create a new player
     factory AssetsAudioPlayer() => AssetsAudioPlayer.newPlayer();
  
positive.code: 
    final String id;
  
    AssetsAudioPlayer._({this.id = _DEFAULT_PLAYER}) {
      _init();
    }
  
  
negative.code:     }
    }
  }
  
  abstract class AudioPlayerHandler {
    Future<String> Function(Audio) onPlay;
  }
  