NavigationContainer

public class NavigationContainer : INavigationContainer
{
    private readonly NavigationPage _page = null;
    public event EventHandler<IViewNavigationArgs> OnPopped;
    private Queue<object> _argQueue = new Queue<object>();
    private AsyncLock _lock = new AsyncLock();
    public string CurrentViewKey { get; set; }

    public NavigationContainer(NavigationPage page)
    {
        _page = page;
        _page.Popped += _page_Popped;
    }

    private void _page_Popped(object sender, NavigationEventArgs e)
    {
        if (OnPopped != null)
        {
            var poppedPage = e.Page as IView;
            var currentPage = _page.CurrentPage as IView;
            var parameter = _argQueue.Count > 0 ? _argQueue.Dequeue() : null;
            OnPopped(this, new ViewNavigationArgs() { Parameter = parameter, CurrentView = currentPage, PoppedView = poppedPage });
        }
    }

    public void SetNavigationBar(bool isVisible, object page)
    {
        var bindableObject = page as BindableObject;
        if (bindableObject != null)
            NavigationPage.SetHasNavigationBar(bindableObject, isVisible);
    }

    public object View { get { return _page; } }

    public bool CanGoBack()
    {
        return _page.Navigation.NavigationStack.Count > 1;
    }

    public async Task PopAsync(object parameter)
    {
        using (var releaser = await _lock.LockAsync())
        {
            _argQueue.Enqueue(parameter);
            await _page.PopAsync();
        }
    }

    public async Task PopAsync()
    {
        using (var releaser = await _lock.LockAsync())
        {
            await _page.PopAsync();
        }
    }

    public async Task PushAsync(object page)
    {
        using (var releaser = await _lock.LockAsync())
        {
            await ThreadHelper.RunOnUIThreadAsync(async () =>
            {
                var xamarinPage = page as Page;

                if (xamarinPage == null)
                    throw new Exception("PushAsync can not push a non Xamarin Page");

                await _page.PushAsync(xamarinPage); // Must be run on the Main Thread
            });
        }
    }
}