buf.append(BASE);
        final int lowTime = (int) (System.currentTimeMillis() >> 32);
        StringUtil.appendHex(buf, lowTime);
        StringUtil.appendHex(buf, RANDOM.nextInt());
        return buf.toString();
    }

    private static byte[] getAddress() {
        try {
            return InetAddress.getLocalHost().getAddress();
        } catch (final UnknownHostException ignore) {

                if ( retries != 1 ) {
                    // backoff, but don't delay the first attempt as there are various reasons that can be fixed
                    // immediately
                    Thread.sleep(500 + RAND.nextInt(1000));
                }
            }
            catch ( InterruptedException e ) {
                log.debug("interrupted sleep in send", e);
            }

            if ( request != null ) {

    static final void randBytes ( Random r, byte[] buffer ) {
        // regular nextBytes is not reproducible if the reads are not aligned
        for ( int i = 0; i < buffer.length; i++ ) {
            buffer[ i ] = (byte) r.nextInt(256);
        }

    }