Callback on mdMenu close
<p>Lets say I have an app that can open menus, for example via <code>$mdOpenMenu($event)</code>.</p>

<p>My app needs to set a callback to get notified when a menu opens or closes.</p>

<p>How can I achieve it? I read the official documentation and I can't seem to find it.</p>

<p>I was looking for something like <code>md-on-remove</code> (used on <code>mdChips</code>), but it doesn't seem to be implemented for <code>mdMenu</code> (<a href="https://github.com/angular/material/issues/7070" rel="noreferrer">issue</a>).</p>