如何在滚动时移动Appbar上的标题

import 'package:flutter/material.dart';

class ScrollableAppBar extends StatefulWidget {
  @override
  _ScrollableAppBarState createState() => _ScrollableAppBarState();
}

class _ScrollableAppBarState extends State<ScrollableAppBar> {
  ScrollController _scrollController;
  double _titleOffset = 0.0;

  @override
  void initState() {
    super.initState();
    _scrollController = ScrollController();
    _scrollController.addListener(_handleScroll);
  }

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

  void _handleScroll() {
    setState(() {
      _titleOffset = _scrollController.offset;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Transform.translate(
          offset: Offset(0, -_titleOffset),
          child: Text('Appbar Title'),
        ),
      ),
      body: ListView.builder(
        controller: _scrollController,
        itemCount: 100,
        itemBuilder: (context, index) {
          return ListTile(
            title: Text('Item $index'),
          );
        },
      ),
    );
  }
}

void main() {
  runApp(MaterialApp(
    home: ScrollableAppBar(),
  ));
}