Function gsk_path_get_closest_point 

pub unsafe extern "C" fn gsk_path_get_closest_point(
    self_: *mut GskPath,
    point: *const graphene_point_t,
    threshold: c_float,
    result: *mut GskPathPoint,
    distance: *mut c_float,
) -> gboolean

Available on crate feature v4_14 only.