public void startRegisterAndCloseNonDurableClientCache() {

    durableClientVM
        .invoke(() -> createCacheClient(
            getClientPool(NetworkUtils.getServerHostName(), PORT1),
            regionName,
            getNonDurableClientDistributedSystemProperties(), true));

    durableClientVM.invoke(() -> DurableClientStatsDUnitTest.registerKey(false));

    durableClientVM.invoke(DurableClientStatsDUnitTest::closeCache);
  }
The DUnitTest checks whether the following Three counts are incremented correctly or not: 1)
DurableReconnectionCount -> Incremented Each time a Proxy present in server for a DurableClient
2) QueueDroppedCount -> Incremented Each time a queue for a durable client is dropped after
durable Timeout 3) EventsEnqueuedWhileClientAwayCount -> Incremented Each time an entry is made
when client is away.

In the given test DurableClient comes up and goes down discreetly with different
DurableClientTimeouts so as to increment the counts
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/DurableClientStatsDUnitTest.java