setVolume method Null safety

Future<void> setVolume(
  1. double volume

set volume of this player audio track

This dose not change system volume. Default value of audio track is 1.0, volume must be greater or equals to 0.0


Future<void> setVolume(double volume) async {
  if (volume < 0) {
    FijkLog.e("$this invoke seekTo invalid volume:$volume");
    return Future.error(
        ArgumentError.value(volume, "setVolume invalid volume"));
  } else {
    await _nativeSetup.future;
    FijkLog.i("$this invoke setVolume $volume");
    return _channel
        .invokeMethod("setVolume", <String, dynamic>{"volume": volume});