Get the CAMetalLayer associated with the given Metal renderer.
Defined in <SDL3/SDL_render.h>
void * SDL_GetRenderMetalLayer(SDL_Renderer *renderer);| SDL_Renderer * | renderer | the renderer to query. | 
(void *) Returns a CAMetalLayer * on success, or NULL if the renderer isn't a Metal renderer.
This function returns void *, so SDL doesn't have to include Metal's headers, but it can be safely cast to a CAMetalLayer *.
This function should only be called on the main thread.
This function is available since SDL 3.2.0.