title: Pretty way to show widget in list on condition
body: <p>I try to show/hide widget in a list depends on the condition.</p>
  <p>All I have come up with is that:</p>
  <pre><code>return Row(
    children: [
      ...isLoading ? [CircularProgressIndicator()] : []
    ]
  );
  </code></pre>
  <p>May you know a prettier way?</p>