Function CGDisplayFade 

pub extern "C-unwind" fn CGDisplayFade(
    token: CGDisplayFadeReservationToken,
    duration: CGDisplayFadeInterval,
    start_blend: CGDisplayBlendFraction,
    end_blend: CGDisplayBlendFraction,
    red_blend: c_float,
    green_blend: c_float,
    blue_blend: c_float,
    synchronous: bool,
) -> CGError

Available on crate features CGDisplayFade and CGError and libc only.