@Test
  public void testTombstoneMessageSentToReplicatesAreNotProcessedInLine() {
    Host host = Host.getHost(0);
    VM vm0 = host.getVM(0);
    VM vm1 = host.getVM(1);

    final String name = "Region";

    createServerRegion(vm0, name, true);
    createEntries(vm0);
    createServerRegion(vm1, name, true);

    try {
      vm1.invoke(() -> {
        DistributionMessageObserver.setInstance(new PRTombstoneMessageObserver());
      });
      destroyEntries(vm0);
      forceGC(vm0);

      vm1.invoke(() -> {
        PRTombstoneMessageObserver mo =
            (PRTombstoneMessageObserver) DistributionMessageObserver.getInstance();
        await().until(() -> {
          return mo.tsMessageProcessed >= 1;
        });
        assertTrue("Tombstone GC message is not expected.", mo.thName.contains(
            "Pooled Message Processor "));
      });

    } finally {
      vm1.invoke(() -> {
        DistributionMessageObserver.setInstance(null);
      });
    }
  }
test that distributed GC messages are sent to clients and properly processed

@param replicatedRegion whether to use a RR or PR in the servers
geode-core/src/distributedTest/java/org/apache/geode/cache30/ClientServerCCEDUnitTest.java