title: Remove scrolling lag with UIScrollView with dynamically rendered items
body: <p>I have a set of items with images, videos and .gif images that are displayed in a UIWebView that are being rendered dynamically when user scrolls to the bottom of the scree and reaches the end of the current UIScrollView offset. When downloading the items from the web I can display an activity indicator that makes user experience smooth and nice, but when I have all the data cached and retrieve it from cache I have a pretty annoying lag when all the items are being rendered at the same time (5 items per loading operation). My question is: <strong>Is it possible to somehow remove the lag from the UIScrollView when rendering items on it? And how can I display an activity indicator when rendering items on main thread?</strong> Specifically the lag happens when user scrolls to bottom, the scroll freezes, all items are rendered and scroll continues to go to bottom with the same force user has dragged it with.</p>
  
  <p>P.S. I cannot use UITableView, so please do not suggest using it instead of scroll view.</p>