public static void createClientCache(String host, Integer port) throws Exception {
    Properties props = new Properties();
    props.setProperty(MCAST_PORT, "0");
    props.setProperty(LOCATORS, "");
    cache = new DeltaPropagationStatsDUnitTest().createCache(props);
    pool = PoolManager.createFactory().addServer(host, port).setMinConnections(1)
        .setSubscriptionEnabled(true).setSubscriptionRedundancy(0).setReadTimeout(10000)
        .setSocketBufferSize(32768).create("DeltaPropagationStatsDunitTestPool");
    AttributesFactory factory = new AttributesFactory();
    factory.setScope(Scope.DISTRIBUTED_ACK);
    factory.setDataPolicy(DataPolicy.NORMAL);
    factory.setPoolName(pool.getName());
    factory.setCloningEnabled(false);

    factory.addCacheListener(new CacheListenerAdapter() {
      @Override
      public void afterCreate(EntryEvent event) {
        if (LAST_KEY.equals(event.getKey())) {
          lastKeyReceived = true;
        }
      }
    });

    RegionAttributes attrs = factory.create();
    cache.createRegion(REGION_NAME, attrs).registerInterest("ALL_KEYS");
  }
Simulates old value null, entry null
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/DeltaPropagationStatsDUnitTest.java