Function igraph_neighborhood_size 

pub unsafe extern "C" fn igraph_neighborhood_size(
    graph: *const igraph_t,
    res: *mut igraph_vector_int_t,
    vids: igraph_vs_t,
    order: igraph_int_t,
    mode: igraph_neimode_t,
    mindist: igraph_int_t,
) -> igraph_error_t