title: Flutter CachedNetworkImageProvider does not have a loading spinner
body: <p>Please let me know how to enable loading spinner for flutter <code>CachedNetworkImageProvider</code>. This works fine with <code>CachedNetworkImage</code>. But the problem is <code>CachedNetworkImage</code> is not a valid image provider.</p>
  
  <pre><code>Container(
    width: 80.0,
    height: 80.0,
    decoration: BoxDecoration(
      shape: BoxShape.circle,
      image: DecorationImage(
        image: CachedNetworkImageProvider('https://pbs.twimg.com/profile_images/945853318273761280/0U40alJG_400x400.jpg'),
      ),
    ),
  )
  </code></pre>