Response response,
                    long timeout ) throws IOException {
            makeKey( request );
            response.isReceived = false;
            try {
                response_map.put( request, response );
                doSend( request );
                response.expiration = System.currentTimeMillis() + timeout;
                while (!response.isReceived) {
                    wait( timeout );

            }
            else {
                curResp.setExpiration(null);
            }

            curResp.setMid(k);
            this.response_map.put(k, curResp);

            Request next = curReq.getNext();
            if ( next != null ) {
                curReq = next;
                curResp = next.getResponse();
            }
            else {