title: Block scroll UIViewCollection before stop scrolling
body: <p>I have class UIViewCollection. I need will block UIViewCollection and unlock after terminating scroll animation UIViewCollection. This method work good but while when i touch to screen it's not complete scrolling </p>
  
  <pre><code>func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) { 
      collectionView.scrollToItem(at: indexPath, at: .centeredHorizontally, animated: true)
  } 
  </code></pre>