Question: Why authRepositoryProvider watch FirebaseAuth.instance?

In `firebase_auth_repository.dart`, `authRepository` watch `firebaseAuthProvider`.

```dart
@Riverpod(keepAlive: true)
FirebaseAuth firebaseAuth(FirebaseAuthRef ref) {
return FirebaseAuth.instance;
}

@Riverpod(keepAlive: true)
AuthRepository authRepository(AuthRepositoryRef ref) {
return AuthRepository(ref.watch(firebaseAuthProvider));
}
```

Llistening to `FirebaseAuth.instance` using `ref.watch`.
This implies that there could be changes FirebaseAuth.instance itself.

Does `FirebaseAuth.instance` actually change automatically?
`FirebaseAuth.instance` implements `static get`, object id will not change.

I would like to know if there are cases where performing operations with Firebase Authentication results in changes to FirebaseAuth.instance.