title: How to determine CoreFoundation _CFXNotificationPost crash
body: <p>I'm facing several crashes when developing a game, probably due to some sort of sound management bugs. This is what my trace says about them:</p>
  
  <pre><code>Thread : Crashed: com.apple.main-thread
  0  libobjc.A.dylib                0x000000019599bbd0 objc_msgSend + 16
  1  CoreFoundation                 0x00000001851d4ae4 __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 20
  2  CoreFoundation                 0x0000000185113220 _CFXNotificationPost + 2060
  3  AVFoundation                   0x0000000183a4af8c __avplayeritem_fpItemNotificationCallback_block_invoke + 5336
  4  libdispatch.dylib              0x0000000195fcd3ac _dispatch_call_block_and_release + 24
  5  libdispatch.dylib              0x0000000195fcd36c _dispatch_client_callout + 16
  ...
  </code></pre>
  
  <p>The line #3 is about AVFoundation and a AVPlayerItem so I guess I have something wrong with my music AVPlayerItems objects, but what... ? :)</p>
  
  <p>Any advice is much appreciated!</p>