pub unsafe extern "C" fn CVDisplayLinkSetOutputCallback(
displayLink: CVDisplayLinkRef,
callback: CVDisplayLinkOutputCallback,
userInfo: *mut c_void,
) -> CVReturnpub unsafe extern "C" fn CVDisplayLinkSetOutputCallback(
displayLink: CVDisplayLinkRef,
callback: CVDisplayLinkOutputCallback,
userInfo: *mut c_void,
) -> CVReturn