public void RaiseOnScroll(float delta, float currentY)
 {
     var args = new ControlScrollEventArgs (delta, currentY);
     OnScroll?.Invoke (this, args);
 }
 public void RaiseOnScroll(float delta, float currentY)
 {
     var args = new ControlScrollEventArgs (delta, currentY);
     if (OnScroll != null) {
         OnScroll (this, args);
     }
 }