title: Animate child when using FutureBuilder
body: <p>I have a <code>FutureBuilder</code> in my app with the conventional structure:</p>
  
  <pre><code>FutureBuilder(
    future: futureData(),
    builder: (context, snapshot) {
      if(snapshot.connectionState == waiting) {
        return Center(
          child: SpinKitCircle(color: Colors.blue),
        );
      } else {
        return ListView.builder();
      }
    }
  )
  </code></pre>
  
  <p>I don't like when it just suddenly pops on the screen, so, my final question is, how can I make the <code>ListView.builder()</code> to get rendered by the <code>FutureBuilder</code> in an animated way?  </p>