setTargetGain method
Sets the target gain to a value in decibels.
Implementation
Future<void> setTargetGain(double targetGain) async {
  _targetGainSubject.add(targetGain);
  if (_active) {
    await (await _player!._platform).androidLoudnessEnhancerSetTargetGain(
        AndroidLoudnessEnhancerSetTargetGainRequest(targetGain: targetGain));
  }
}