CMSampleBuffer to Audio Data

Question

How do I take the sampleBuffer and translate it into Data for audio?

Here is the function that I use to get the sampleBuffer

func captureOutput(_ : AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
    // Do something with sampleBuffer to get it into audio Data   
   // Make it come out in a data Object.
}