Navigation bar disable with Xamarin.forms 2.5.0.280555, How

Question

After update Xamarin.forms version 2.4.0* to 2.5.0.280555, Navigation bar doesn't show. When I go back to 2.4.0 its working fine. So how I can enable my Navigation bar in X.F 2.5.0.280555

 

NavigationPage.SetHasNavigationBar(this, true); is not working