String? title;

String newTitle = title!;

String? title;
// String? title = 'test';
bool? isEmpty = title?.isEmpty;

String? title;
String newTitle = title ?? 'default';

late String title;
void main(List<String> args) {
  title = 'dart';
  print(title);
}

class WPHttpService extends GetxService {
  late final Dio _dio;

  @override
  void onInit() {
    ...

    _dio = Dio(options);

    ...
  }
}