如何在FutureBuilder小部件的构建器函数中等待？

Future<String> fetchData() async {
  // 模拟一个异步操作，例如网络请求
  await Future.delayed(Duration(seconds: 2));
  return 'Hello, World!';
}

Widget build(BuildContext context) {
  return FutureBuilder<String>(
    future: fetchData(),
    builder: (BuildContext context, AsyncSnapshot<String> snapshot) {
      if (snapshot.connectionState == ConnectionState.waiting) {
        // 显示加载中的UI
        return CircularProgressIndicator();
      } else if (snapshot.hasError) {
        // 显示错误信息的UI
        return Text('Error: ${snapshot.error}');
      } else {
        // 显示数据的UI
        return Text('Data: ${snapshot.data}');
      }
    },
  );
}