code: final void handleKeyId(String kId) {
          String oldKeyId = getKeyId();
          if (oldKeyId != null && !oldKeyId.equals(kId)) {
              createDataStreamingEvent(oldKeyId, this.props);
          }
          this.keyId = kId;
      }
docs: For recording the key id of the current record.
  
  @param kId the key id {@link String}.