Hidden static variable

protocol CurrentUserManager {
    var currentUser: User { get }
}

class CurrentUserManagerIml: CurrentUserManager {
  
   /// Current user cached in memory
   /// obtainCurrentUser - static method, obtain User model from data base/file/e.t.c.
   private static var currentUser: User = obtainCurrentUser()
  
   var currentUser: User {
        return Class.currentUser
   }
}

/* Usage */ 

class SomeClass {
   
   lazy var currentUser: User = {
      
      /// If you haven't Dependency Injection for class
      let user = CurrentUserManagerIml().currentUser
      
      return user
   }()
}