@After
  public void tearDown() {
    for (VM vm : toArray(getAllVMs(), getController())) {
      vm.invoke(() -> {
        DistributionMessageObserver.setInstance(null);
        CountDownLatch latch = SLEEP.get();
        while (latch != null && latch.getCount() > 0) {
          latch.countDown();
        }
      });
    }
    disconnectAllFromDS();
  }
This is a test of how persistent distributed regions recover. This test makes sure that when
multiple VMs are persisting the same region, they recover with the latest data during recovery.
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/persistence/PersistentRecoveryOrderDUnitTest.java