SplashActivity.cs

 [Activity(Theme = "@style/MyTheme.Splash", MainLauncher = true, NoHistory = true)]
    public class SplashActivity : AppCompatActivity
    {
        static readonly string TAG = "X:" + typeof(SplashActivity).Name;

        public override void OnCreate(Bundle savedInstanceState, PersistableBundle persistentState)
        {
            base.OnCreate(savedInstanceState, persistentState);

            // Create your application here
            // app Init
            new App(this);
        }

        // Launches the startup task
        protected override void OnResume()
        {
            base.OnResume();
            Task startupWork = new Task(() => { StartupApp(); });
            startupWork.Start();             
        }

        async void StartupApp()
        {
 
            Log.Debug(TAG, "Startup work is finished - starting MainActivity.");
            StartActivity(new Intent(Application.Context, typeof(MainActivity)));
        }
    }