@Override
    public void process(DistributionMessage msg) {
      try {
        if (msg instanceof FetchVersionReplyMessage) {
          FetchVersionReplyMessage reply = (FetchVersionReplyMessage) msg;
          tag = reply.tag;
          if (logger.isTraceEnabled(LogMarker.DM_VERBOSE)) {
            logger.trace(LogMarker.DM_VERBOSE, "FetchVersionResponse return tag is {}", tag);
          }
        }
      } finally {
        super.process(msg);
      }
    }
A processor to capture the VersionTag returned by RemoteFetchVersion message.
geode-core/src/main/java/org/apache/geode/internal/cache/tx/RemoteFetchVersionMessage.java