Function make_gray_to_unfused 

pub(crate) fn make_gray_to_unfused<T: Copy + Default + PointeeSizeExpressible + 'static + Send + Sync, const BUCKET: usize>(
    src_layout: Layout,
    dst_layout: Layout,
    gray_linear: Box<[f32; 65536]>,
    red_gamma: Box<[T; 65536]>,
    green_gamma: Box<[T; 65536]>,
    blue_gamma: Box<[T; 65536]>,
    bit_depth: usize,
    gamma_lut: usize,
) -> Result<Arc<dyn TransformExecutor<T> + Sync + Send>, CmsError>
where
    u32: AsPrimitive<T>,