static CallbackHandler()
 {
     mouseButtonDownCB = new MouseButtonDownDelegate(fireButtonDown);
     mouseButtonUpCB   = new MouseButtonUpDelegate(fireButtonUp);
     mouseMoveCB       = new MouseMoveDelegate(fireMoved);
     mouseWheelCB      = new MouseWheelDelegate(fireWheel);
 }
        private static extern IntPtr NativeMouse_new(IntPtr osWindow, MouseButtonDownDelegate mouseButtonDownCB, MouseButtonUpDelegate mouseButtonUpCB, MouseMoveDelegate mouseMoveCB, MouseWheelDelegate mouseWheelCB
#if FULL_AOT_COMPILE
                                                     , IntPtr instanceHandle
#endif
                                                     );