如何在Flutter中获取iOS的APNs token进行推送？

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

// 初始化通知设置
FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
    FlutterLocalNotificationsPlugin();

void main() {
  // 初始化Flutter应用程序
  WidgetsFlutterBinding.ensureInitialized();

  // 配置通知设置
  var initializationSettingsAndroid =
      AndroidInitializationSettings('app_icon');
  var initializationSettingsIOS = IOSInitializationSettings();
  var initializationSettings = InitializationSettings(
      android: initializationSettingsAndroid, iOS: initializationSettingsIOS);
  flutterLocalNotificationsPlugin.initialize(initializationSettings);

  // 运行Flutter应用程序
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter APNs Token Demo',
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  String apnsToken = '';

  @override
  void initState() {
    super.initState();
    // 获取APNs token
    getAPNSToken();
  }

  Future<void> getAPNSToken() async {
    // 请求获取APNs token
    String token = await flutterLocalNotificationsPlugin
        .resolvePlatformSpecificImplementation<
            IOSFlutterLocalNotificationsPlugin>()
        ?.requestNotificationPermissions(
          const IosNotificationSettings(
              sound: true, badge: true, alert: true, provisional: false),
        )
        ?.then((_) async {
      return await flutterLocalNotificationsPlugin
          .resolvePlatformSpecificImplementation<
              IOSFlutterLocalNotificationsPlugin>()
          ?.getApnsToken();
    });

    setState(() {
      apnsToken = token ?? '获取APNs token失败';
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter APNs Token Demo'),
      ),
      body: Center(
        child: Text('APNs Token: $apnsToken'),
      ),
    );
  }
}