TabBarView notifies the View without delay⏱️

I encountered an interesting problem throgh a project, with many open issues on the Web, such as:

• TabController notifies correct index with a delay (after the tab scroll animation ends) #88875

• TabController listener triggers with delay on swipe #89371

• Describe how to listen for page updates in TabBar and TabBarView when using DefaultTabController #53155

I demonstrate the ability of TabBarView to notify the view with the correct index without delay. ✅
Documentation in the the rows of the code. ✍️ The soul of the project:

// indexController.change() comes from IndexController, which is declared in main.dart.

var _ = DefaultTabController.of(context);
_?.animation!.addListener(() {
  indexController.change(newValue:(_.indexIsChanging)?_.index:_.animation!.value.round());
});

🎥 Here is a preview GIF, where you can see, how it works: