Xamarin Forms + Installing Firebase plugin = errors

[Xamarin Forms Shell App + Firebase iOS Auth plugin v. 6.9.2]

Last day I added the Google Firebase functionalities to my project, but unfortunately I add some errors just after installing the Firebase Plugin.

> Xamarin Forms (Shell app) + iOS Firebase errors adding latest package:

....iOS/MTOUCH: Error MT5210: Native linking failed, undefined symbol: _GULIsLoggableLevel. Please verify that all the necessary frameworks have been referenced and native libraries are properly linked in. (MT5210) (*.iOS) 

I found some solutions, and finally the iOS SDK worked with my Xamarin Forms Shell app... Unfortunately, with Xamarin Forms, we still take too much time to solve this kind of problem. 
What did I do ?

iOS project properties

=> Set the "entitlements file property" to a default file (the *.plist file can be empty):

=> iOS Build options:

- Add 'mtouch' argument: --registrar:static

- and try to set linker behavior to SDKs only

Then initialize Firebase in your code:

In your iOS 'appDelegate' file, you can initialize Firebase like that:

FinishedLaunching(UIApplication app, NSDictionary options)
{
	global::Xamarin.Forms.Forms.Init();
	

	Firebase.Core.App.Configure();
	

	...
    

}

==> Clean ALL then rebuild your project. It should be ok now.