@Override
    public void afterProcessMessage(ClusterDistributionManager dm, DistributionMessage message) {
      if (message instanceof DestroyOperation.DestroyMessage) {
        // Notify the destroy with smaller version to continue.
        synchronized (this) {
          notifyAll();
        }
      }
      if (message instanceof DistributedTombstoneOperation.TombstoneMessage) {
        tombstoneGcLatch.countDown();
      }
    }
The purpose of this test is for a non-replicate region scenario to get the oldest tombstone
and validate that it matches the tombstone of the entry we removed. This is done through a
client
as a client is required to have this non-replicate tombstone.
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/versions/TombstoneDUnitTest.java