How to reuse the contents of the same widget in flutter?

I want to use the same instance of a widget in multiple places, changes in one place will be synchronized to another place.

But using the same instance in multiple places looks like multiple different instances.

So how can I achieve the feat?

  var test = InAppWebView(
    // ...

  Widget build(BuildContext context) {
    return Scaffold(
      body: PageView(
        children: [
          test,  // widget one
          test,  // widget two
        controller: _pageController,
        physics: NeverScrollableScrollPhysics(),
        onPageChanged: onPageChanged,

I'm use flutter_inappbrowser.

Widget one and widget two use the same instance, but when I open the web page with widget one, widget two is unaffected.

I want widget one and widget two to be the same widget, that when widget one changes, widget two will also be affected.