title: "with" keyword in Flutter
body: <p>I was reading a class like:</p>
  
  <pre><code>class SplashScreenState extends State&lt;SplashScreen&gt;
      with SingleTickerProviderStateMixin {
   ...
   ...
  }
  </code></pre>
  
  <p>And I am just wondering what <strong>with</strong> keyword refers in this context and why do we use it ?</p>