apollo-client/src/main/java/com/ctrip/framework/apollo/util/ConfigUtil.java/ConfigUtil/initPropertyNamesCacheEnabled
class ConfigUtil:  private void initPropertyNamesCacheEnabled() {
    propertyNamesCacheEnabled = getPropertyBoolean(ApolloClientSystemConsts.APOLLO_PROPERTY_NAMES_CACHE_ENABLE,
            ApolloClientSystemConsts.APOLLO_PROPERTY_NAMES_CACHE_ENABLE_ENVIRONMENT_VARIABLES,
            propertyNamesCacheEnabled);
  }