public static void waitForLastKey() {
    WaitCriterion wc = new WaitCriterion() {
      @Override
      public boolean done() {
        return ClientToServerDeltaDUnitTest.lastKeyReceived;
      }

      @Override
      public String description() {
        return "Last key NOT received.";
      }
    };
    GeodeAwaitility.await().untilAsserted(wc);
  }
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