title: StatefulBuilder vs StatefulWidget
body: <p>What is the difference between <code>StatefulBuilder</code> and <code>StatefulWidget</code>? When one should be used instead of the other?<br>
  At first glance they seem similar.<br>
  <code>StatefulBuilder</code> is defined:  </p>
  
  <blockquote>
    <p>A platonic widget that both has state and calls a closure to obtain its child widget</p>
  </blockquote>
  
  <p>While <code>StatefulBuilder</code> is defined:  </p>
  
  <blockquote>
    <p>A widget that has mutable state</p>
  </blockquote>