Dart 在 Flutter 中从树中临 timeshift 除时保留小部件状态

我正在try 保留小部件的状态，以便如果我暂时从小部件树中删除有状态小部件，然后稍后重新添加它，则小部件将具有与删除它之前相同的状态.下面是我的一个简化示例:

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  bool showCounterWidget = true;
  @override
  Widget build(BuildContext context) {

    return Material(
      child: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            showCounterWidget ? CounterButton(): Text("Other widget"),
            SizedBox(height: 16,),
            FlatButton(
              child: Text("Toggle Widget"),
              onPressed: (){
                setState(() {
                showCounterWidget = !showCounterWidget;
              });
                },
            )
          ],
        ),
      ),
    );
  }
}

class CounterButton extends StatefulWidget {
  @override
  _CounterButtonState createState() => _CounterButtonState();
}

class _CounterButtonState extends State<CounterButton> {
  int counter = 0;

  @override
  Widget build(BuildContext context) {
    return MaterialButton(
      color: Colors.orangeAccent,
      child: Text(counter.toString()),
      onPressed: () {
        setState(() {
          counter++;
        });
      },
    );
  }
}

理想情况下，我不希望状态重置，因此计数器不会重置为0，我如何保留计数器小部件的状态？