public TimeUnit getConnTimeToLiveTimeUnit() {
        return connTimeToLiveTimeUnit;
    }
@Test
    void testGetConnTimeToLiveTimeUnit() {
        HttpClientConfig config = HttpClientConfig.builder().setConnectionTimeToLive(4000, TimeUnit.SECONDS).build();
        assertEquals(TimeUnit.SECONDS, config.getConnTimeToLiveTimeUnit());
    }