title: Swift 4 Unwind segue not working on navigation controller
body: <p>I am working on an app in Swift 4 and I am trying to unwind a segue. I have a Table View Controller, When the user selects a cell, the segue happens to a navigation controller which has a relationship root view controller with another controller I have <code>UIViewController</code>. In the <code>UIViewController</code> I have a <code>UIButton</code> inside Navigation Items, I have unwind set with the UIButton by selecting the button and dragging to exit and I have the unwind code inside the <code>UITableViewController</code> like so:</p>
  
  <pre><code>    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
              if segue.identifier == "segueRSVP" {
              }
          }
  
  
  
      @IBAction override func unwind(for unwindSegue: UIStoryboardSegue, towardsViewController subsequentVC: UIViewController) {
          print("Here")
      }
  </code></pre>
  
  <p>But nothing happens, it doesn't even get triggered.</p>
  
  <p>Here are my screenshots:</p>
  
  <p><a href="https://i.stack.imgur.com/vHJq1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/vHJq1.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/ejaI5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ejaI5.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/coGcZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/coGcZ.png" alt="enter image description here"></a></p>