 several log format may be active at the same time. The rationale is that
            the user might want to see a non-exhaustive log in his terminal using
            a human friendly format, while having a detailed full log in a file with
            a format dedicated to automated processing.
          </li>
<li class="listitem">
            each logger <span class="emphasis"><em>indicates</em></span> its default output stream.
            some logger may prefer to output to one of the standard stream wh