@Override
  public VersionTag findVersionTagForBulkOp(EventID eventID) {
    if (eventID == null) {
      return null;
    }
    ThreadIdentifier threadID = createThreadIDFromEvent(eventID);
    BulkOperationHolder evh = recordedBulkOpVersionTags.get(threadID);
    if (evh == null) {
      if (logger.isDebugEnabled()) {
        logger.debug("search for version tag failed as no events are recorded for {}",
            threadID.expensiveToString());
      }
      return null;
    }

    synchronized (evh) {
      if (logger.isDebugEnabled()) {
        logger.debug("search for version tag located event holder for {}: {}",
            threadID.expensiveToString(), evh);
      }
      return evh.getEntryVersionTags().get(eventID);
    }
  }
Record a version tag for a bulk operation.
geode-core/src/main/java/org/apache/geode/internal/cache/event/DistributedEventTracker.java