title: Get the width of a UIBarButtonItem
body: <p>I'm trying to get the width of a <code>UIBarButtonItem</code>.</p>
  
  <p>This doesn't work:</p>
  
  <pre><code>barbuttonitem.customView.frame.size.width
  </code></pre>
  
  <p>And this won't work, either:</p>
  
  <pre><code>barbuttonitem.width
  </code></pre>