callJoin method
Implementation
Future<Map<dynamic, dynamic>> callJoin(String callID, dynamic config) async {
  final result = await promiseToFuture(
          ZIM.getInstance()!.callJoin(callID, _mapToJSObject(config)))
      .catchError(_handleError);
  Map map = _jsObjectToMap(result);
  return {'callID': map['callID'], 'info': map};
}