title: Flutter Container() vs SizedBox() for dummy empty
body: <p>I am curious about this. I have seen many example using <code>Container()</code> for dummy hidden widget, for example, when loading has completed, then we <code>setState(() { _isLoaded = true; });</code>.
  So we can use the state like this, right?</p>
  
  <pre><code>return _isLoaded ? Container() : LoaderWidget();
  </code></pre>
  
  <p>Or maybe using <code>SizedBox()</code> is actually better because it don't take much parameters and often used for padding anyway?</p>
  
  <pre><code>return _isLoaded ? SizedBox() : LoaderWidget();
  </code></pre>
  
  <p>Or am I wrong?</p>