 write timestamp at the end of the request formatted using the
        enhanced SimpleDateFormat pattern <code>xxx</code></li>
    </ul>

    <p>All formats supported by SimpleDateFormat are allowed in <code>%{xxx}t</code>.
    In addition the following extensions have been added:</p>
    <ul>
    <li><b><code>sec</code></b> - number of seconds since the epoch</li>
    <li><b><code>msec</code></b> - number of milliseconds since the epoch</li>
    <li><b><code>msec_frac</code></b> - millisecond fraction</li>