Implement Bottom Nav Bar using Stacked and Navigation Service

We were working on custom bottom navigation bar using `GestureDetector` to navigate through different states. But it's increasing the Firebase Reads every the screen is built. With your recent update where `IndexTrackingViewModel` is included, we want to understand how to implement with a multi-route App and NavigationService.

In our scenario we have Splash Screen Navigates to HomeScreen. Bottom Navigation is visible in three screens, each of the following screen uses a custom stateless class `CustomBottomNavigation` which returns `BottomNavigationBar`.
1. HomeScreen with Multi Widgets and Navigation Text Links
2. FirebaseList Screen with Sliver List (OnTap of List Item) Firebase List Item Detail Screen.
3. User Screen with Sliver List (OnTap of List Item) Firebase List Item Detail Screen.

Right now the navigation is controlled using `Router` as explained in your tutorial.

Do we have to extend `IndexTrackingViewModel` to each of the above three viewmodels which are currently extending `BaseModel`?

まず、言及されているエントリーポイントである IndexTrackingViewModel、BaseModel、Router、CustomBottomNavigation を読み、その後 HomeScreen、FirebaseList、UserScreen のナビゲーションフローを追跡します。3 つの viewmodel が IndexTrackingViewModel をどのように使用するかについての判断を含め、不要な画面の再構築と Firebase の読み取りを避ける、明確に文書化された、または動作する複数ルートのボトムナビゲーションアプローチがあれば完了です。

索引モデルが issue の本文から書いたものです。