code: @Override
      public Map<String, Object> toSource() {
          Map<String, Object> sourceMap = new HashMap<>();
          if (crawlingInfoId != null) {
              addFieldToSource(sourceMap, "crawlingInfoId", crawlingInfoId);
          }
          if (createdTime != null) {
              addFieldToSource(sourceMap, "createdTime", createdTime);
          }
          if (key != null) {
              addFieldToSource(sourceMap, "key", key);
          }
          if (value != null) {
              addFieldToSource(sourceMap, "value", value);
          }
          return sourceMap;
      }
docs: ======