FirebaseInstanceId.Instance.Token is depricated and returns null in Xamarin.Android using Xamarin.Firebase.Messaging
FirebaseInstanceId.Instance.Token
is deprecated in favour of GetInstanceId<InstanceIdResult>()
,
So GetInstanceId< InstanceIdResult >() is the recommended way,
This is how you can consume it,
var instanceIdResult = await FirebaseInstanceId.Instance.GetInstanceId().AsAsync<IInstanceIdResult>();
var token = instanceIdResult.Token;