public void add(String element) {
    addAsync(element).toCompletableFuture().join();
  }
@Test
  @Timeout(5)
  public void testEventuallyExpires() throws InterruptedException {
    final FaultTolerantRedisCluster redisCluster = REDIS_CLUSTER_EXTENSION.getRedisCluster();
    final CardinalityEstimator estimator = new CardinalityEstimator(redisCluster, "test", Duration.ofMillis(100));
    estimator.add("1");
    long count;
    do {
      count = redisCluster.withCluster(conn -> conn.sync().pfcount("cardinality_estimator::test"));
      Thread.sleep(1);
    } while (count != 0);
  }