@Override
    protected void process(ClusterDistributionManager dm) {
      ReplyMessage reply = new ReplyMessage();
      reply.setProcessorId(processorId);
      reply.setRecipient(getSender());
      byte[] returnValue = new byte[SMALL_BUFFER_SIZE * 6];
      reply.setReturnValue(returnValue);
      System.out.println("<" + Thread.currentThread().getName() +
          "> sending reply with return value size "
          + returnValue.length + " using " + getReplySender(dm));
      getReplySender(dm).putOutgoing(reply);
    }
SerialAckedMessageWithBigReply requires conserve-sockets=false and acts to send
a large reply message to the sender. You must have already created a cache in the
sender and receiver VMs and registered this class with the DataSerializableFixedID
of SERIAL_ACKED_MESSAGE. Don't forget to reset the registration to
SerialAckedMessage at the end of the test.
geode-core/src/upgradeTest/java/org/apache/geode/ClusterCommunicationsDUnitTest.java