apollo-common/src/main/java/com/ctrip/framework/apollo/common/dto/GrayReleaseRuleItemDTO.java/GrayReleaseRuleItemDTO/GrayReleaseRuleItemDTO
class GrayReleaseRuleItemDTO:  public GrayReleaseRuleItemDTO(String clientAppId) {
    this(clientAppId, Sets.newHashSet(), Sets.newHashSet());
  }