title: How to convert NSURL to CFURL in swift?
body: <p>Here is the code I am running in the Swift playground:</p>
  
  <pre><code>import Foundation
  import AudioToolbox
  
  var audioURL:NSURL = NSURL.fileURLWithPath("/path")
  
  var audioFile:UnsafePointer&lt;AudioFileID&gt;
  
  var audioCfUrl:CFURL = audioURL as CFURL
  
  AudioFileOpenURL(audioCfUrl!, Int8(kAudioFileReadPermission), 0, &amp;audioFile)
  </code></pre>
  
  <p>On the last line I am getting the error:</p>
  
  <pre><code>'NSURL' is not a subtype of CFURL
  </code></pre>