/**
     * @return
     * @throws IOException
     */
    private int negotiateWrite(final CommonServerMessageBlockRequest req, final boolean setmid) throws IOException {
        if (setmid) {
            makeKey(req);
        } else {
            req.setMid(0);
            this.mid.set(1);
        }
        final int n = req.encode(this.sbuf, 4);