public static extern void ulAppRun(ULApp app);
public static extern void ulAppQuit(ULApp app);
public static extern ULMonitor ulAppGetMainMonitor(ULApp app);
public static extern ULRenderer ulAppGetRenderer(ULApp app);
public static extern bool ulAppIsRunning(ULApp app);
public static extern void ulAppSetUpdateCallback(ULApp app, ULUpdateCallback callback, IntPtr user_data);
public static extern ULWindow ulAppGetWindow(ULApp app);
public static extern void ulAppSetWindow(ULApp app, ULWindow window);
public static extern void ulDestroyApp(ULApp app);