如何在GoogleMap和堆栈中使用DraggableScrollableSheet？

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Google Map with DraggableScrollableSheet',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Google Map with DraggableScrollableSheet'),
      ),
      body: Stack(
        children: [
          GoogleMap(
            initialCameraPosition: CameraPosition(
              target: LatLng(37.7749, -122.4194),
              zoom: 12,
            ),
          ),
          Positioned(
            left: 0,
            right: 0,
            bottom: 0,
            child: DraggableScrollableSheet(
              initialChildSize: 0.3,
              minChildSize: 0.1,
              maxChildSize: 0.8,
              builder: (BuildContext context, ScrollController scrollController) {
                return Container(
                  color: Colors.white,
                  child: ListView.builder(
                    controller: scrollController,
                    itemCount: 20,
                    itemBuilder: (BuildContext context, int index) {
                      return ListTile(
                        title: Text('Item $index'),
                      );
                    },
                  ),
                );
              },
            ),
          ),
        ],
      ),
    );
  }
}