title: Angular multi/select with async pipe
body: <p>Here's an example of well implemented select and multiselect form controls using Angular Material:</p>
  
  <p><a href="https://stackblitz.com/edit/mat-select-search" rel="nofollow noreferrer">https://stackblitz.com/edit/mat-select-search</a></p>
  
  <p>The drawback is that they use hardcoded data (array).</p>
  
  <p>How do I implement the same, but using async data (read from API, as Observable), not subscribing direcly to the values, but using <code>async</code> pipe in the view and showing progress indicator if needed?</p>