如何使用flutter在窗口中显示通知？

import 'package:flutter_local_notifications/flutter_local_notifications.dart';

class NotificationService {
  final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
      FlutterLocalNotificationsPlugin();
      
  // 其他通知相关的逻辑代码...
}

class NotificationService {
  //...

  Future<void> initialize() async {
    const AndroidInitializationSettings initializationSettingsAndroid =
        AndroidInitializationSettings('app_icon');
    final InitializationSettings initializationSettings =
        InitializationSettings(android: initializationSettingsAndroid);
    await flutterLocalNotificationsPlugin.initialize(initializationSettings);
  }
  
  //...
}

class NotificationService {
  //...

  Future<void> showNotification(
      String title, String body, Map<String, dynamic> payload) async {
    const AndroidNotificationDetails androidPlatformChannelSpecifics =
        AndroidNotificationDetails(
            'your channel id', 'your channel name', 'your channel description',
            importance: Importance.max,
            priority: Priority.high,
            showWhen: false);

    const NotificationDetails platformChannelSpecifics =
        NotificationDetails(android: androidPlatformChannelSpecifics);

    await flutterLocalNotificationsPlugin.show(
        0, title, body, platformChannelSpecifics,
        payload: json.encode(payload));
  }
  
  //...
}

NotificationService notificationService = NotificationService();
await notificationService.initialize();

// 显示通知
notificationService.showNotification('标题', '内容', {'data': '附加数据'});