docs: public AckEvent unmarshall(JsonNode json) {
          return new AckEvent()
              .withFragmentNumber(getTextField(json, FRAGMENT_NUMBER))
              .withFragmentTimecode(getLongField(json, FRAGMENT_TIMECODE))
              .withAckEventType(AckEventType.of(getTextField(json, ACK_EVENT_TYPE)))
              .withErrorCode(getTextField(json, ERROR_CODE))
              .withErrorId(getIntegerField(json, ERROR_ID));
      }