title: flutter - correct way to create a box that starts at minHeight, grows to maxHeight
body: <p>I have a container that I want to start off at a minimum size and grow (if its contents grow while user is adding content) to a maximum size, then stop.</p>
  
  <p>The correct widget for this seems to be ConstrainedBox, like so:</p>
  
  <pre><code>new ConstrainedBox(
    constraints: new BoxConstraints(
      minHeight: 35.0,
      maxHeight: 60.0,
    ),
    child: ...child with growing content (has default height 25.0)...
  ),
  </code></pre>
  
  <p>however, this starts the box off at the maxHeight.</p>
  
  <p>I tried to use hasBoundedHeight, but can not seem to construct the correct syntax for it or find an example in documentation.</p>
  
  <p>What is the best way to get the box working as described?</p>