ough the event object using <code>$event-&gt; app</code>, as shown below:</p>

<div class="code code">
<pre class="code">// ...
&nbsp;
public function onStart(BaseEvent $event)
{
    $event-&gt;app-&gt;set('app.timer.start', microtime(true));
}</pre>
</div>

<p>If you want to add plugins to your own book, create a directory called <code>Plugins</code> inside the <code>Resources</code> directory of your book (create the latter one if it doesn't exist). Then add as many PHP classes as you want, but make their