static CallbackHandler()
 {
     windowMovedCallback       = new WindowEventDelegate(windowMoved);
     windowResizedCallback     = new WindowEventDelegate(windowResized);
     windowClosingCallback     = new WindowClosingDelegate(windowClosing);
     windowClosedCallback      = new WindowEventDelegate(windowClosed);
     windowFocusChangeCallback = new WindowEventDelegate(windowFocusChange);
 }
        private static extern IntPtr NativeWindowListener_Create(WindowEventDelegate windowMovedCallback, WindowEventDelegate windowResizedCallback, WindowClosingDelegate windowClosingCallback, WindowEventDelegate windowClosedCallback, WindowEventDelegate windowFocusChangeCallback
#if FULL_AOT_COMPILE
                                                                 , IntPtr instanceHandle
#endif
                                                                 );