public static void closeCache() {
    if (cache != null && !cache.isClosed()) {
      cache.close();
      cache.getDistributedSystem().disconnect();
      lastKeyReceived = false;
    }
  }
This test does the following for single key (<b> full cycle</b>):<br>
1)Verifies that client-server, peer-peer and server-client processing delta<br>
geode-cq/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/ClientToServerDeltaDUnitTest.java