[Question] "Out of sync" data in Firestore

### [REQUIRED] Please fill in the following fields:

* Unity editor version: 2020.3.9f1
* Firebase Unity SDK version: 7.2.0
* Source you installed the SDK: Unity Package Manager with tgz
* Problematic Firebase Component: Firestore
* Other Firebase Components in use: Auth, Crashlytics, Remote Config
* Additional SDKs you are using:
* Platform you are using the Unity editor on: Windows
* Platform you are targeting: Android
* Scripting Runtime: IL2CPP

### [REQUIRED] Please describe the question here:

I stumbled about the following information when looking into Firestore's cache behavior:

> These things (_set(), update(), or delete()_) will happen eventually, if the app comes back online and the SDK is able to sync. But if the app process dies while offline and is relaunched online, those methods of tracking the completion of the operation will no longer work.

When I understand this correctly, data saved to the cache before the app dies/stops is not automatically updated to the Firestore backend when the app launches again.

Is this correct and when yes, what would be the best way to handle the "out of sync" data only present in the cache?