uniq

static VALUE
lazy_uniq(VALUE obj)
{
    rb_block_call_func *const func =
        rb_block_given_p() ? lazy_uniq_iter : lazy_uniq_func;
    return lazy_set_method(rb_block_call(rb_cLazy, id_new, 1, &obj,
                                         func, 0),
                           0, 0);
}