private static extern void toggl_on_promotion( IntPtr context, TogglDisplayPromotion cb);
private static extern void toggl_on_promotion( IntPtr context, TogglDisplayPromotion cb);
private static extern void toggl_on_promotion( IntPtr context, TogglDisplayPromotion cb);
private static extern void toggl_on_promotion( IntPtr context, TogglDisplayPromotion cb);