title: Status Bar Style - Swift 3 - change at any time
body: <p>I'm finding it hard to change the status bar style programatically.</p>
  
  <p>I see how to statically set it for each ViewController using a combo of (in <em>ViewController.swift</em>):</p>
  
  <pre><code>override var preferredStatusBarStyle: UIStatusBarStyle {
      return UIStatusBarStyle.default
  }
  </code></pre>
  
  <p>and (in <em>info.plist</em>):</p>
  
  <pre><code>View controller-based status bar appearance = YES
  </code></pre>
  
  <p>...</p>
  
  <p>I'm looking to change it whenever I want!</p>