Function composite_framebuffer_fade 

pub fn composite_framebuffer_fade<D>(
    target: &mut D,
    outgoing: &[Rgb565],
    width: usize,
    height: usize,
    outgoing_opacity: u8,
) -> Result<(), D::Error>
where
    D: DrawTarget<Color = Rgb565> + PixelRead,

Cross-fade a frozen outgoing framebuffer over an already-rendered incoming target using the same opacity curve as ScreenTransitionEffect::Fade.