如何在Flutter中创建多行SnackBar？

import 'package:flutter/material.dart';

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Multi-line SnackBar Example'),
        ),
        body: MyWidget(),
      ),
    );
  }
}

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Center(
      child: RaisedButton(
        child: Text('Show SnackBar'),
        onPressed: () {
          Scaffold.of(context).showSnackBar(
            SnackBar(
              content: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                mainAxisSize: MainAxisSize.min,
                children: <Widget>[
                  Text('Line 1'),
                  Text('Line 2'),
                ],
              ),
              duration: Duration(seconds: 3),
            ),
          );
        },
      ),
    );
  }
}

void main() {
  runApp(MyApp());
}