If you're using the application main callbacks, your SDL_AppIterate() function will be called while Windows is moving and resizing your window. If not, then SDL will send an SDL_EVENT_WINDOW_EXPOSED event for your window and you can use an event watcher to redraw your window directly from the callback.
Fixes https://github.com/libsdl-org/SDL/issues/1059
Closes https://github.com/libsdl-org/SDL/pull/4836