public ApacheHttpClient.Builder getHttpClientBuilder() {
    return _httpClientBuilder;
  }
@Test
  public void testGetHttpClientBuilder() {
    PinotConfiguration pinotConfig = new PinotConfiguration();
    S3Config cfg = new S3Config(pinotConfig);
    Assert.assertNull(cfg.getHttpClientBuilder());

    pinotConfig.setProperty("httpclient.maxConnections", 100);
    pinotConfig.setProperty("httpclient.socketTimeout", "PT1M10S");
    pinotConfig.setProperty("httpclient.connectionTimeout", "PT2M20S");
    pinotConfig.setProperty("httpclient.connectionTimeToLive", "3m30s");
    pinotConfig.setProperty("httpclient.connectionAcquisitionTimeout", "4m40s");
    cfg = new S3Config(pinotConfig);
    Assert.assertNotNull(cfg.getHttpClientBuilder());
  }