title: How can I await modal form dismissal using Xamarin.Forms?
body: <p>Using Xamarin.Forms how can I use make an async method that waits for the form to dismiss? If I use </p>
  
  <pre class="lang-cs prettyprint-override"><code>await Navigation.PushModalAsync(page);
  </code></pre>
  
  <p>it will return once the animation is finished not when the page is dismissed.</p>
  
  <p>I want a to create modal Task SignInAsync method that return true if sign-in is successful.</p>