title: Angular form binding with async pipe to set the model
body: <p>If I have an observable I want to use as the default value for a form binding is there a way to have the async pipe set the model value of the binding?</p>
  <pre><code>&lt;input type=&quot;text&quot; name=&quot;value&quot; [ngModel]=&quot;defaultValue$ | async&quot;
    (ngModelChange)=&quot;model.value = $event&quot;&gt;
  </code></pre>
  <p>This works fine but the value emitted by <code>defaultValue$</code> does not set <code>model.value</code>, it only populates the input.</p>
  <p>Is there a way to use the async pipe to both write the value of ngModel and set model.value?</p>