title: UITableView tableView(_:didEndDisplaying:forRowAt:) not being called
body: <p>I am trying to use this callback to detect when cells are available to be reused. According to the documentation the signature is:</p>
  
  <pre><code>optional func tableView(_ tableView: UITableView, 
         didEndDisplaying cell: UITableViewCell, 
         forRowAt indexPath: IndexPath)
  </code></pre>
  
  <p>but actually, this doesn't compile with Xcode 7.3 and Swift. I think IndexPath should be NSIndexPath and the _ has to be removed. So I get:</p>
  
  <pre><code>@objc func tableView(tableView: UITableView, 
      didEndDisplaying cell: UITableViewCell, 
      forRowAt indexPath: NSIndexPath) {
  </code></pre>
  
  <p>However, this is never called.</p>
  
  <p>The dequeue function is called fine (below) and the table works otherwise:</p>
  
  <pre><code>@objc func tableView(tableView: UITableView,
      cellForRowAtIndexPath indexPath: NSIndexPath) -&gt; UITableViewCell
  </code></pre>
  
  <p>so that would imply my data-source is working ok.</p>
  
  <p>I am wondering if this is some non-functioning part of the API.</p>
  
  <p>(P.S. I don't recall why the @objc is there, but removing it didn't make any difference).</p>