title: Is it possible to use ListView.builder inside of CustomScrollView?
body: <p>Is it possible to use <code>ListView.builder</code> (or something similar) inside of a <code>CustomScrollView</code>? I have a <code>CustomScrollView</code> like this:</p>
  
  <pre class="lang-dart prettyprint-override"><code>return Scaffold(
    body: CustomScrollView(
      slivers: [
        SliverAppBar(...),
        SliverList(delegate: SliverChildListDelegate(children))
      ],
    ),
  );
  </code></pre>
  
  <p>This works great, but in my actual scenario the list could have thousands of items, so I do not want to pass them all in to <code>SliverChildListDelegate</code>. I want to use <code>ListView.builder</code> (or something similar) to build the items as they are scrolled into view. I was expecting there to be a <code>.builder</code> constructor on either <code>SliverList</code> or  <code>SliverChildListDelegate</code> but I don't see anything like that. Am I missing something?</p>