如何在flutter中的选项卡栏后面添加阴影？

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('Tab Bar with Shadow'),
        ),
        body: Container(
          decoration: BoxDecoration(
            boxShadow: [
              BoxShadow(
                color: Colors.grey.withOpacity(0.5), // 阴影颜色
                spreadRadius: 5, // 阴影的扩展半径
                blurRadius: 10, // 阴影的模糊程度
                offset: Offset(0, 3), // 阴影的偏移量
              ),
            ],
          ),
          child: DefaultTabController(
            length: 3,
            child: Scaffold(
              appBar: AppBar(
                bottom: TabBar(
                  tabs: [
                    Tab(text: 'Tab 1'),
                    Tab(text: 'Tab 2'),
                    Tab(text: 'Tab 3'),
                  ],
                ),
              ),
              body: TabBarView(
                children: [
                  // Tab 1 内容
                  Center(child: Text('Tab 1')),
                  // Tab 2 内容
                  Center(child: Text('Tab 2')),
                  // Tab 3 内容
                  Center(child: Text('Tab 3')),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }
}