if (setmid) {
            makeKey(req);
        } else {
            req.setMid(0);
            this.mid.set(1);
        }
        final int n = req.encode(this.sbuf, 4);
        Encdec.enc_uint32be(n & 0xFFFF, this.sbuf, 0); /* 4 byte ssn msg header */

        if (log.isTraceEnabled()) {
            log.trace(req.toString());
            log.trace(Hexdump.toHexString(this.sbuf, 4, n));
        }