如何在customScrollView中检测和运行滚动到底部的加载函数

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('CustomScrollView Example')),
        body: MyScrollableContent(),
      ),
    );
  }
}

class MyScrollableContent extends StatefulWidget {
  @override
  _MyScrollableContentState createState() => _MyScrollableContentState();
}

class _MyScrollableContentState extends State<MyScrollableContent> {
  final ScrollController _scrollController = ScrollController();
  List<String> items = List.generate(20, (index) => 'Item $index');
  bool isLoading = false;

  @override
  void initState() {
    super.initState();
    _scrollController.addListener(_scrollListener);
  }

  @override
  void dispose() {
    _scrollController.dispose();
    super.dispose();
  }

  void _scrollListener() {
    if (_scrollController.position.atEdge) {
      if (_scrollController.position.pixels == _scrollController.position.maxScrollExtent) {
        _loadMoreItems();
      }
    }
  }

  Future<void> _loadMoreItems() async {
    if (isLoading) return;
    setState(() {
      isLoading = true;
    });
    // Simulate network call or heavy operation
    await Future.delayed(Duration(seconds: 2));
    setState(() {
      items.addAll(List.generate(10, (index) => 'Item ${items.length + index}'));
      isLoading = false;
    });
  }

  @override
  Widget build(BuildContext context) {
    return CustomScrollView(
      controller: _scrollController,
      slivers: <Widget>[
        SliverList(
          delegate: SliverChildBuilderDelegate(
            (BuildContext context, int index) {
              return ListTile(title: Text(items[index]));
            },
            childCount: items.length,
          ),
        ),
        if (isLoading)
          SliverToBoxAdapter(
            child: Center(child: CircularProgressIndicator()),
          ),
      ],
    );
  }
}