@Override
    public boolean add(String e) {
        return get(addAsync(e));
    }
@Test
    public void testPollFirst() {
        RLexSortedSet set = redisson.getLexSortedSet("simple");
        Assertions.assertNull(set.pollFirst());

        set.add("a");
        set.add("b");
        set.add("c");

        Assertions.assertEquals("a", set.pollFirst());
        assertThat(set).containsExactly("b", "c");
    }