public static void SetExtender(DependencyObject element, PullToRefreshExtender value)
 {
     (element.GetValue(ExtenderProperty) as PullToRefreshExtender)?.Detach(element);
     element.SetValue(ExtenderProperty, value);
     value?.Attach(element);
 }
 public static void SetExtender(DependencyObject element, PullToRefreshExtender value)
 {
     (element.GetValue(ExtenderProperty) as PullToRefreshExtender)?.Detach(element);
     element.SetValue(ExtenderProperty, value);
     value?.Attach(element);
 }