title: wrong size and positon of UITextView after creating Box for its contours
body: <p>I was trying wrap test into enclosing box by means of boundingrectwithsize function.</p>
  
  <pre><code>func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -&gt; CGSize {
      if let messageText = messages?[indexPath.item].text {
          let size = CGSize(width:view.frame.width,height: 1000)
          let options = NSStringDrawingOptions.usesLineFragmentOrigin.union(.usesFontLeading)
          let estimatedFrame = NSString(string: messageText).boundingRect(with: size, options: options, attributes: [NSFontAttributeName: UIFont.systemFont(ofSize: 18)], context: nil)
          return CGSize(width: view.frame.width,height: estimatedFrame.height)
      }
  
      return CGSize(width:view.frame.width,height: 100)
  }
  </code></pre>
  
  <p>}</p>
  
  <p>But the output was something weird and  i am very confused</p>
  
  <p><a href="https://i.stack.imgur.com/SgIqk.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SgIqk.png" alt="enter image description here"></a></p>
  
  <p>why it did always cutting last string? It seemed to me i was using right NSString.DrawingOptions and especially usesFontLeading calculates the size but why it cut the last string? </p>