@Override
    public Set<K> keySet() {
        return keySet(null);
    }
@Test
    public void testKeySet() {
        Map<SimpleKey, SimpleValue> map = redisson.getMap("simple");
        map.put(new SimpleKey("1"), new SimpleValue("2"));
        map.put(new SimpleKey("33"), new SimpleValue("44"));
        map.put(new SimpleKey("5"), new SimpleValue("6"));

        assertThat(map.keySet()).containsOnly(new SimpleKey("33"), new SimpleKey("1"), new SimpleKey("5"));
    }