Animation did full rotation

Question

I've animation, my UIImageView spins on its orbit by 360, What I want to do is to know when UIImageView does it full rotation from 0 to 360, is it even possible ?

below is my animation codes

        let orbit = CAKeyframeAnimation(keyPath: "position")
        var affineTransform = CGAffineTransform(rotationAngle: 0.0)
        affineTransform = affineTransform.rotated(by: CGFloat(Double.pi))
        let circlePath = UIBezierPath(arcCenter: CGPoint(x: 0,y: 0), radius:  CGFloat(1), startAngle: CGFloat(0), endAngle:CGFloat(Double.pi * 2), clockwise: true)
        orbit.path = circlePath.cgPath
        orbit.duration = 4
        orbit.isAdditive = true
        //orbit.repeatCount = 50000 * 50000
        orbit.repeatCount = .infinity
        orbit.calculationMode = CAAnimationCalculationMode.paced
        orbit.rotationMode = CAAnimationRotationMode.rotateAuto

        bigCookie.layer.add(orbit, forKey: "orbit")