title: How to select all items which listed in recyclerview?
body: <p>I have list of items inside of recyclerview, and they are multiple selectable.</p>
  
  <p>I want to have select button to select all, and if selected deselect all. I didn't see any option to iterate through RecyclerView.Adapter to do that. How can I implement that? </p>
  
  <p>Thank you.</p>