Pick up on Mainactivity events in App.xaml.Cs

Question

I have it on my App.xaml.Cs

CrossFirebasePushNotification.Current.OnNotificationReceived += (s, p) =>
{                    
   System.Diagnostics.Debug.WriteLine("Received");
};

When I receive messages, ie have something on p.data, as I shoot at my Mainactivity badge?

In the Activity Oncreate I have

badge = new Badge();

And now I need to create a method or something to fire the badge counter, like this:

Contador++;
badge.count(Contador);

I’m not getting anything in the App from Mainactivity and not the other way around, even adding the appropriate references.

That lambda is inside the constructor class App.xaml.Cs.