ReplayKit.swift

func runRecording() {
    guard recorder.isAvailable else {
        print("Recording is not available at this time.")
        return
    }

    recorder.startRecording{ [unowned self] (error) in
        guard error == nil else {
            print("There was an error starting the recording.")
            return
        }
    }
}

func stopRecording() {
    recorder.stopRecording { [unowned self] (preview, error) in
        guard preview != nil else {
            print("Preview controller is not available.")
            return
        }

        let alert = UIAlertController(title: "Recording Finished", message: "Would you like to edit or delete your recording?", preferredStyle: .alert)

        let deleteAction = UIAlertAction(title: "Delete", style: .destructive, handler: { (action: UIAlertAction) in
            self.recorder.discardRecording(handler: { () -> Void in
                print("Recording suffessfully deleted.")
            })
        })

        let editAction = UIAlertAction(title: "Edit", style: .default, handler: { (action: UIAlertAction) -> Void in
            preview?.previewControllerDelegate = self
            self.present(preview!, animated: true, completion: nil)
        })

        alert.addAction(editAction)
        alert.addAction(deleteAction)
        self.present(alert, animated: true, completion: nil)
    }
}