Marking a variable with IBOutlet allows it to be connected with a Storyboard component through the Interface Builder. Allowing such a
variable to be accessed outside the class, may result in other classes making assignments that override the automatic dependency injection from the
Storyboard itself.
Noncompliant code example
@IBOutlet var label: UILabel! // Noncompliant
Compliant solution
@IBOutlet private var label: UILabel!
