title: Angular: are nested async pipe usage safe?
body: <p>I couldn't find any documentation related to this, so here it is. I have this usage of async pipe in a template:</p>
  
  <pre><code>&lt;component [aliases]="(users$ | async).profile.aliases$ | async"/&gt;
  </code></pre>
  
  <p>Is <code>aliases$</code> subscription correctly unsubscribed when <code>users$</code> emits? And what if there is an <code>*ngIf</code> on the wrapping element?</p>