func drawProgress(toValue: Float) {
    let circlePath = UIBezierPath(arcCenter: CGPoint(x: self.contentView.frame.width / 2, y: self.contentView.frame.height / 2), radius: 30, startAngle: 0, endAngle: 6.28, clockwise: true)
    // create its cooresponding layer
    let circleLayer = CAShapeLayer()
    circleLayer.frame = self.contentView.bounds
    circleLayer.path = circlePath.CGPath
    circleLayer.strokeColor = UIColor.blackColor().CGColor
    circleLayer.fillColor = self.contentView.backgroundColor?.CGColor
    circleLayer.lineWidth = 1.0
    self.contentView.layer.addSublayer(circleLayer)

    // create the animation
    let pathAnimation = CABasicAnimation(keyPath: "strokeEnd")
    pathAnimation.duration = 0.1
    pathAnimation.fromValue = NSNumber(float: 0.0)
    pathAnimation.toValue = NSNumber(float: toValue)

    // apply the animation to path
    circleLayer.addAnimation(pathAnimation, forKey: "strokeEnd")
}

func URLSession(session: NSURLSession, downloadTask: NSURLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {

  //...other code above to get the correct cell for index path, etc
  myCell.drawProgress(toValue:download.progress)
  //trackCell.progressView.progress = download.progress
 }

//myCell.progressView.progress = download.progress