iOS Swift Custom Circular Progress bar

import UIKit
class CircularProgressView: UIView {
// First create two layer properties
 private var circleLayer = CAShapeLayer()
 private var progressLayer = CAShapeLayer()
 
 override init(frame: CGRect) {
  super.init(frame: frame)
  createCircularPath()
 }

 required init?(coder aDecoder: NSCoder) {
  super.init(coder: aDecoder)
  createCircularPath()
 }
 
 func createCircularPath() {
  let circularPath = UIBezierPath(
  arcCenter: CGPoint(x: frame.size.width / 2.0, y: frame.size.height / 2.0), 
    radius: 80, 
    startAngle: -.pi / 2,
    endAngle: 3 * .pi / 2, 
    clockwise: true)
    
  circleLayer.path = circularPath.cgPath
  circleLayer.fillColor = UIColor.clear.cgColor
  circleLayer.lineCap = .round
  circleLayer.lineWidth = 20.0
  circleLayer.strokeColor = UIColor.black.cgColor
  
  progressLayer.path = circularPath.cgPath
  progressLayer.fillColor = UIColor.clear.cgColor
  progressLayer.lineCap = .round
  progressLayer.lineWidth = 10.0
  progressLayer.strokeEnd = 0
  progressLayer.strokeColor = UIColor.red.cgColor
  
  layer.addSublayer(circleLayer)
  layer.addSublayer(progressLayer)
 }
 
  func progressAnimation(duration: TimeInterval) {
    let circularProgressAnimation = CABasicAnimation(keyPath: "strokeEnd")
    circularProgressAnimation.duration = duration
    circularProgressAnimation.toValue = 1.0
    circularProgressAnimation.fillMode = .forwards
    circularProgressAnimation.isRemovedOnCompletion = false
    progressLayer.add(circularProgressAnimation, forKey: "progressAnim")
  }
}

reference: https://medium.com/@imsree/custom-circular-progress-bar-in-ios-using-swift-4-b1a9f7c55da