[Question] Do I need to care about the log "Error: status is pending return the pending future" on iOS ?

### Please fill in the following fields:

* Unity editor version: 2020.3.19f1
* Firebase Unity SDK version: 8.5.0
* Source you installed the SDK: .tgz
* Problematic Firebase Component: Messaging
* Other Firebase Components in use: Core, Analytics
* Additional SDKs you are using: none
* Platform you are using the Unity editor on: Windows, Mac
* Platform you are targeting: **iOS**
* Scripting Runtime: IL2CPP

### Please describe the question here:
I always get the log `Error: status is pending return the pending future` when I call `FirebaseMessaging.RequestPermissionAsync` in the continuation function of `Firebase.FirebaseApp.CheckAndFixDependenciesAsync().ContinueWithOnMainThread`.

Except this error log, everything works fine.
The prompt to request permission to receive notifications was shown as expected. The notification also received as expected.

Is there any way to fix it? Or I can ignore this error log?

(Related issue: #821)
(It can be 100% reproduced from [cloud messaging quickstart](https://github.com/firebase/quickstart-unity/blob/master/messaging/testapp/Assets/Firebase/Sample/Messaging/UIHandler.cs).)