apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/config/BizConfig.java/BizConfig/longPollingTimeoutInMilli
class BizConfig:  public long longPollingTimeoutInMilli() {
    int timeout = getIntProperty("long.polling.timeout", DEFAULT_LONG_POLLING_TIMEOUT);
    // java client's long polling timeout is 90 seconds, so server side long polling timeout must be less than 90
    return 1000 * checkInt(timeout, 1, 90, DEFAULT_LONG_POLLING_TIMEOUT);
  }