Function label_components_threshold_model 

pub fn label_components_threshold_model<'a>(
    arena: &'a Bump,
    grayscale: &[u8],
    grayscale_stride: usize,
    threshold_map: &[u8],
    width: usize,
    height: usize,
    use_8_connectivity: bool,
    min_area: u32,
    margin: i16,
) -> LabelResult<'a>

Threshold-model-aware connected component labeling.