release method
Implementation
Future<void> release(MediaType mediaType) async {
if (!_isInit || mediaType != _currentMediaType) return;
_isInit = false;
_currentMediaType = MediaType.none;
await _engine.leaveChannel();
await _engine.enableLocalVideo(false);
await _engine.enableLocalAudio(false);
await _engine.stopVideoPreview();
await _engine.release();
}