Does supplying instantiated classes in a dart enhanced enum lead to performance issues in flutter?

Question

I would like to use an enhanced enum in flutter to supply the widget and app bar to be used on a scaffold with bottom navigation.

Will it lead to performance issues? Will the classes get instantiated each time I use the enum anywhere in the code?

Example for the enum:

enum BottomNavPage {
  foo(widget: const FooWidget(), appBar: const FooAppBar()),
  bar(widget: const BarWidget(), appBar: const BarAppBar());

  final Widget widget;
  final AppBar appBar;
  const BottomNavPage({this.widget, this.appBar});
}

This is how it might be used in the code (e.g. inside a stateful widget):

Widget build(BuildContext context) {
  return Scaffold(
    appBar: _currentPage.appBar,
    body: _currentPage.widget,
    bottomNavigationBar: BottomNavBarWidget());
}

So far so good. Would below examples create new instances of FooWidget and BarWidget each time it is used somewhere?

// Setting a new Page
setState(() => _currentPage = BottomNavPage.foo);

// Action based on current page
switch(_currentPage) {
  case BottomNavPage.foo:
    // Do something
    break;
  case BottomNavPage.bar:
  default:
    // Something else
    break;
}