Function erode_rect_u8_into 

pub fn erode_rect_u8_into(
    input: ImageView<'_, u8, 1>,
    element: &StructuringElement,
    iterations: usize,
    border: BorderMode<u8, 1>,
    output: &mut [u8],
    workspace: &mut RectMorphologyWorkspace,
) -> VisionResult<()>

Erodes into caller-owned packed output using reusable scratch storage.