title: Flutter sliver container
body: <p>I'm new to flutter and I'm not able to achieve the layout I want.</p>
  
  <p>I have one sliverAppBar with 3 tabs. The content of one of the tabs has to be a ScrollView compound by one container with fixed size(with an image as background) and a ListView.</p>
  
  <p>I've tried to do this with a CustomScrollView but I don't know how to create the container as it is not a sliver.</p>
  
  <p>Can you point me in the right direction?</p>
  
  <p>Regards, Diego. </p>