protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);
            Xamarin.Essentials.Platform.Init(this, savedInstanceState);
            SetContentView(Resource.Layout.activity_main);

            FManager = FragmentManager;
            BottomNavigationView navigation = FindViewById <BottomNavigationView>(Resource.Id.navigation);

            navigation.SetOnNavigationItemSelectedListener(this);
            OnNavigationItemSelected(navigation.Menu.GetItem(0));
            sMessageEngine = Nearby.GetMessageEngine(this);
            RequestPermissions();
            sMessageEngine.RegisterStatusCallback(new MyStatusCallback()).AddOnCompleteListener(new TaskListener(this, " RegisterStatusCallback")).AddOnFailureListener(new TaskListener(this, " RegisterStatusCallback"));
        }