hangup method

Implementation

Future<TUIActionCallback> hangup() {
  Completer<TUIActionCallback> completer = Completer();
  String userData = Tools.generateUserData("Call_hangup");
  _actionCallback2Future(userData, completer);
  final params = [];
  _callEngineSDK.Dart_CallEngineCallAPI(
      'hangup'.toNativeUtf8().cast(),
      jsonEncode(params).toNativeUtf8().cast(),
      userData.toNativeUtf8().cast());
  return completer.future;
}