@Override
    public long countSubscribers() {
        return commandExecutor.get(countSubscribersAsync());
    }
@Test
    public void testCountSubscribers() {
        RTopic topic1 = redisson.getTopic("topic", LongCodec.INSTANCE);
        assertThat(topic1.countSubscribers()).isZero();
        int id = topic1.addListener(Long.class, (channel, msg) -> {
        });
        assertThat(topic1.countSubscribers()).isOne();
        topic1.removeListener(id);
        assertThat(topic1.countSubscribers()).isZero();
    }