title: isRunning returns NO even though AVCaptureSession is running
body: <p>I am capturing video with AVCaptureSession, and everything is working just fine on iOS 6.1. However, I have been trying to check from another thread whether my capture session is running via isRunning method. However, the method returns NO regardless of whether my capture session is running or not.</p>
  
  <p>However, if I called isRunning method on the main thread; I get the correct value.</p>
  
  <p>Does anyone have a good explanation for this?</p>