title: Tracking what all items of a list are currently visible on the screen
body: <p>Suppose I have a recyclerview with 10 items. Out of these 10, 0 - 4 are visible in one go. On scrolling down, 0th element goes away from the screen and 5th one enters. I want to track these events - where I get to know that elements 0 - 4 are visible and then on scrolling, 1-5 are.</p>
  
  <p>Is there anyway to achieve this? I want to keep track of how long a user is spending time on a particular items of the recyclerview. </p>