apollo-common/src/main/java/com/ctrip/framework/apollo/common/dto/GrayReleaseRuleItemDTO.java/GrayReleaseRuleItemDTO/toString
class GrayReleaseRuleItemDTO:  @Override
  public String toString() {
    return toStringHelper(this).add("clientAppId", clientAppId)
        .add("clientIpList", clientIpList)
        .add("clientLabelList", clientLabelList).toString();
  }