@Override
    protected void appendFields(StringBuilder buff) {
      super.appendFields(buff);
      buff.append("; key=");
      buff.append(key);
      if (eventId != null) {
        buff.append("; eventId=").append(eventId);
      }
    }
This operation updates Version stamp of an entry if entry is available and entry version stamp
has same DSID as in event's version tag.
geode-core/src/main/java/org/apache/geode/internal/cache/UpdateEntryVersionOperation.java