title: When I go routes forth-and-back are page states preserved?
body: <p>Is a. page widget; b. its state recreated anew or remains the same as it was on the previous show of the same page by:</p>
  <ol>
  <li><code>Navigator.pushNamed()</code></li>
  <li><code>Navigator.pop()</code>?</li>
  </ol>