public CountdownPage(CountdownViewModel viewModel)
 {
     NavigationPage.SetHasNavigationBar(this, false);
     InitializeComponent();
     ViewModel = viewModel;
 }
 public CountdownPage(int? delay)
 {
     NavigationPage.SetHasNavigationBar(this, false);
     InitializeComponent();
     ViewModel = new CountdownViewModel(delay);
 }