apollo-client/src/main/java/com/ctrip/framework/apollo/util/ConfigUtil.java/ConfigUtil/ConfigUtil
class ConfigUtil:  public ConfigUtil() {
    warnLogRateLimiter = RateLimiter.create(0.017); // 1 warning log output per minute
    initRefreshInterval();
    initConnectTimeout();
    initReadTimeout();
    initCluster();
    initQPS();
    initMaxConfigCacheSize();
    initLongPollingInitialDelayInMills();
    initAutoUpdateInjectedSpringProperties();
    initPropertiesOrdered();
    initPropertyNamesCacheEnabled();
    initPropertyFileCacheEnabled();
  }