CodeCallTracker facilitates executing code exclusively on its first call
example:
class ViewController: UIViewController { private let code = CodeCallTracker() override func viewWillAppear(animated: Bool) { super.viewWillAppear(animated: animated) if code.isFirstTimeCall() { // do something only on first call of viewWillAppear } else { // do something on other calls of viewWillAppear } } override func updateViewConstraints() { if code.isFirstTimeCall() { // do something only on first call of updateViewConstraints } else { // do something on other calls of updateViewConstraints } super.updateViewConstraints() } }