public static void verifyDeltaSent(Integer deltas) {
    CacheClientNotifier ccn = ((CacheServerImpl) cache.getCacheServers().toArray()[0]).getAcceptor()
        .getCacheClientNotifier();

    int numOfDeltasSent = ((CacheClientProxy) ccn.getClientProxies().toArray()[0]).getStatistics()
        .getDeltaMessagesSent();
    assertTrue("Expected " + deltas + " deltas to be sent but " + numOfDeltasSent + " were sent.",
        numOfDeltasSent == deltas);
  }
This test ensures that a server sends delta bytes to a client even if that client is not
interested in that event but is getting the event only because the event satisfies a CQ which
the client has registered with the server.
geode-cq/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/ClientToServerDeltaDUnitTest.java