Mixing a CocosSharp game with UIViewControllers - ios

Question

I'm creating a CocosSharp game with several additional native screens which I'm going to implement using native iOS UIViewController. The flow is the following:
On app startup I'm creating UINavigationViewController and initial view with my custom main menu:
public override void FinishedLaunching(UIApplication app)
{
MainWindow = new UIWindow(UIScreen.MainScreen.Bounds);
var rootViewStoryboard = UIStoryboard.FromName("GameMenu", null);
var rootView = rootViewStoryboard.InstantiateViewController("GameMenu");
var navigationController = new UINavigationController(rootView);
MainWindow.RootViewController = navigationController;
MainWindow.MakeKeyAndVisible();
}
public partial class GameMenu : UIViewController
{
public GameMenu(IntPtr handle)
: base(handle)
{
}
public override void ViewDidLoad()
{
base.ViewDidLoad();
btnStartGame.TouchUpInside += (sender, e) => NavigationController.PresentViewController(new GameScene(), false);
}
}
One of the actions leads to another UIViewController (modal) where CocosSharp game is created:
public partial class GameScene : UIViewController
{
public GameScene()
{
}
public override void ViewDidLoad()
{
base.ViewDidLoad();
_application = new CCApplication();
_application.ApplicationDelegate = new GameAppDelegate();
_application.StartGame();
_application.MainWindow.DisplayStats = true;
OnStopGame();
}
}
Finally on certain event (in my case in 5 sec) I'm trying to finish a game and return back to the main menu:
public async Task OnStopGame()
{
await Task.Delay(5000);
_application.ExitGame();
NavigationController.DismissViewController(false, null);
}
As a result I get empty black screen, background music continue to run, no main menu is displayed.
How should I properly navigate from CocosSharp game to a native controller and back? Can they live in parallel?