anchor.diff:            break;
           case METHOD_CURRENT:
             if (call.arguments == null) {
  -            final current = _current.value;
  +            final current = _current.valueOrNull;
               if (current != null) {
                 final finishedPlay = Playing(
                   audio: current.audio,
  
positive.code:   ///
    Future<void> seekBy(Duration by) async {
      // only if playing a song
      final playing = current.value;
      if (playing != null) {
        final totalDuration = playing.audio.duration;
  
  
negative.code:   void onAudioReplacedAt(int index, bool keepPlayingPositionIfCurrent) {
      assetsAudioPlayer._updatePlaylistIndexes();
      if (assetsAudioPlayer._playlist!.playlistIndex == index) {
        final currentPosition = assetsAudioPlayer.currentPosition.valueOrNull;
        final isPlaying = assetsAudioPlayer.isPlaying.valueOrNull ?? false;
        //print('onAudioReplacedAt/ currentPosition : $currentPosition');
        if (keepPlayingPositionIfCurrent && currentPosition != null) {
  