public static ClientTombstoneMessage gc(LocalRegion region,
      Map<VersionSource<?>, Long> regionGCVersions, EventID eventId) {
    return new ClientTombstoneMessage(TOperation.GC, region, regionGCVersions, eventId);
  }
GC operation for non-partitioned regions
geode-core/src/main/java/org/apache/geode/internal/cache/tier/sockets/ClientTombstoneMessage.java