title: Sticky headers on SliverList
body: <p>I've seen new flutter video and seen some interesting. (It's not typical sticky header or expandable list, so I don't know how to name it)</p>
  
  <p><a href="https://youtu.be/ORiTTaVY6mM?t=19" rel="noreferrer">Video</a> - watch from 0:20</p>
  
  <p>Does anybody know how can I create such type of list with headers using SliverList?</p>
  
  <p><a href="https://i.stack.imgur.com/4WFxP.png" rel="noreferrer"><img src="https://i.stack.imgur.com/4WFxP.png" alt="enter image description here"></a></p>