如何在Flutter上的SliverAppBar中添加标签条？

import 'package:flutter/material.dart';

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> with SingleTickerProviderStateMixin {
  TabController _tabController;

  @override
  void initState() {
    super.initState();
    _tabController = TabController(length: 3, vsync: this);
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: CustomScrollView(
        slivers: <Widget>[
          SliverAppBar(
            title: Text('My App'),
            backgroundColor: Colors.blue,
            expandedHeight: 200,
            flexibleSpace: FlexibleSpaceBar(
              background: Image.network(
                'https://example.com/image.jpg',
                fit: BoxFit.cover,
              ),
            ),
            bottom: PreferredSize(
              preferredSize: Size.fromHeight(48),
              child: TabBar(
                controller: _tabController,
                tabs: <Widget>[
                  Tab(text: 'Tab 1'),
                  Tab(text: 'Tab 2'),
                  Tab(text: 'Tab 3'),
                ],
              ),
            ),
          ),
          SliverFillRemaining(
            child: TabBarView(
              controller: _tabController,
              children: <Widget>[
                // Content for Tab 1
                Container(
                  color: Colors.red,
                ),
                // Content for Tab 2
                Container(
                  color: Colors.green,
                ),
                // Content for Tab 3
                Container(
                  color: Colors.blue,
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}