ServerMessageBlock nextReq = curReq.getAndx();
                if ( nextReq == null ) {
                    break;
                }
                ServerMessageBlock nextResp = curResp.getAndx();
                nextReq.setResponse(nextReq);

                if ( ! ( nextReq instanceof AndXServerMessageBlock ) || ! ( nextResp instanceof AndXServerMessageBlock )) {
                    break;