如何在flutter上使用provider中的shared_preferences ...？

dependencies:
  flutter:
    sdk: flutter
  provider: ^5.0.0
  shared_preferences: ^2.0.0

import 'package:provider/provider.dart';
import 'package:shared_preferences/shared_preferences.dart';

class PreferencesProvider with ChangeNotifier {
  SharedPreferences _prefs;

  PreferencesProvider() {
    _initPrefs();
  }

  Future<void> _initPrefs() async {
    _prefs = await SharedPreferences.getInstance();
    notifyListeners();
  }

  String getSomeValue() {
    return _prefs.getString('someValue') ?? '';
  }

  Future<void> setSomeValue(String value) async {
    await _prefs.setString('someValue', value);
    notifyListeners();
  }
}

void main() {
  runApp(
    ChangeNotifierProvider(
      create: (context) => PreferencesProvider(),
      child: MyApp(),
    ),
  );
}

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final preferencesProvider = Provider.of<PreferencesProvider>(context);
    final someValue = preferencesProvider.getSomeValue();

    return Text(someValue);
  }
}

preferencesProvider.setSomeValue('New Value');