How to Use file in /Library/Sounds as notification sound in ios flutter

Question

I just got a request: Can you download sound file from remote server and make it a notification sound?

Here is my code (for ios)

//package i used
import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import 'package:dio/dio.dart';
import 'package:path/path.dart' as pathService;
import 'package:path_provider/path_provider.dart';

//Download file we needed
final iosLibraryDir = await getApplicationLibrary();
final soundFilename = 'notification1.wav';
final downloadPath = pathService.join(iosLibraryDir.path, 'Sounds', soundFilename); 
Dio dio = Dio();
await dio.download(remoteURL, downloadPath);

//set up notification
final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();

await flutterLocalNotificationsPlugin.initialize(
  InitializationSettings(
      iOS: IOSInitializationSettings(requestSoundPermission: true)
);

await flutterLocalNotificationsPlugin.show(
  1,
  'Test Title',
  'Test Body',
  NotificationDetails(
    iOS: IOSNotificationDetails(
      presentSound: true,
      sound: soundFilename
    )
  )
);

Notification shown but no sound played I also try path like '/Library/Sounds/notification1.wav' and full path report from getApplicationLibrary(), but none of them worked.

Is this caused by ios cannot found the path or Apple's security policy not allowed it?