دکمه back در webview

سلام
از سایتی که با vue js درست کردم یک webview با فلاتر زدم اما دکمه back رو که میزنم کلا برنامه بسته می شه

// Copyright 2018 The Flutter team. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/material.dart';
import 'package:webview_flutter/webview_flutter.dart';
import 'package:flutter_localizations/flutter_localizations.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
        var materialApp = MaterialApp(
        localizationsDelegates: [
          GlobalCupertinoLocalizations.delegate,
          GlobalMaterialLocalizations.delegate,
          GlobalWidgetsLocalizations.delegate,
        ],
        supportedLocales: [
          Locale("fa", "IR"), // OR Locale('ar', 'AE') OR Other RTL locales
        ],
        locale: Locale("fa", "IR"), // OR Locale('ar', 'AE') OR Other RTL locales          
          title: 'مجله',
          home: Scaffold(
          appBar: AppBar(
              title: Text('مجله'),
            ),            
            body: WebView(
              initialUrl: 'https://domain.ir',
              javascriptMode: JavascriptMode.unrestricted,
            ),
          ),          
          debugShowCheckedModeBanner: false,
          theme: ThemeData(
            primarySwatch: Colors.blue,
            visualDensity: VisualDensity.adaptivePlatformDensity,
          ),
    );
    return materialApp;
  }
}

ممنون می شم اگه همین بخش رو کد آماده ای دارید بگید درست کنم