如何将一个变量从导航器设置为全局变量，以便在flutter应用程序的所有页面中都可用？

dependencies:
  flutter:
    sdk: flutter
  provider: ^6.0.0

import 'package:flutter/material.dart';

class AppState extends ChangeNotifier {
  String globalVariable = '';

  void setGlobalVariable(String value) {
    globalVariable = value;
    notifyListeners();
  }
}

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

void main() {
  runApp(
    MultiProvider(
      providers: [
        ChangeNotifierProvider(create: (context) => AppState()),
      ],
      child: MyApp(),
    ),
  );
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'My App',
      home: HomePage(),
    );
  }
}

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final appState = Provider.of<AppState>(context);

    return Scaffold(
      appBar: AppBar(
        title: Text('Home Page'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text('Global Variable: ${appState.globalVariable}'),
            ElevatedButton(
              onPressed: () {
                appState.setGlobalVariable('New Value');
              },
              child: Text('Change Global Variable'),
            ),
          ],
        ),
      ),
    );
  }
}