/** {@inheritDoc} */
 @Override
 public Object invoke(Object payload, boolean isRequestResponse) throws Exception {
   MessageExchange myExchange = new MessageExchange(payload);
   buffer.put(myExchange);
   if (!isRequestResponse) {
     return null;
   }
   return myExchange.waitForResponse();
 }
 /** {@inheritDoc} */
 @Override
 public void stop() {
   buffer.stop();
 }
 /**
  * Starts the one and only job instance in a separate Thread. Should be called exactly one time
  * before the operation is stopped.
  *
  * @param arguments {@inheritDoc}
  */
 protected void start(WorkloadListener listener) {
   buffer.setWorkloadListener(listener);
 }