ugin that <em>listens</em> to this events and executes some code when an specific event is notified.</p>

<p>Technically, plugins are based on the subscribers defined by the event dispatcher component of Symfony2. They are regular PHP classes whose name always ends with the word <code>Plugin</code>. The following code shows the source of <code>TimerPlugin.php</code>, the plugin used by <strong>easybook</strong> to measure how long it takes to publish a book:</p>

<div class="code code">
<pre class="code">&l