How to add Scrollbar to Listview in Flutter?

import 'package:flutter/material.dart';

main(List<String> args) {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @
override

  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyHome(),
    );
  }
}

class MyHome extends StatelessWidget {
  @
override

  Widget build(BuildContext context) {
    return Scaffold(
      body: Scrollbar(
        thickness: 10,
        child: ListView(
          children: List.generate(
            20,
            (int i) => Card(
              child: Center(
                child: ListTile(
                  title: Text(
                    'This is item ' + i.toString(),
                  ),
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}