dispose method
Implementation
@override
Future<void> dispose()async {
_player.dispose();
_player.textureId.removeListener(_onListener);
await _currentPosition.close();
await _isBuffering.close();
await _isPlaying.close();
await _volume.close();
await _playSpeed.close();
await _playlistFinished.close();
await _current.close();
await _playerState.close();
await _onReadyToPlay.close();
}