+ # The application leaves the active state but is still partially visible
+ #
+ # It may still be visible in the background.
+ # It may then go back to `on_resume` or `on_stop`.
+ fun on_pause do end
+
+ # The application is completely hidden from the user
+ #
+ # It may then be destroyed (`on_destroy`) or go back to `on_start`.
+ fun on_stop do end
+
+ # The application is being destroyed
+ fun on_destroy do end
+
+ # The application may be destroyed soon, save its state for a future `on_restore_state`
+ fun on_save_state do end
+
+ # The application is launching, restore its state from a previous `on_save_state`
+ fun on_restore_state do end