AuthManager.swift

enum AuthError: Error {
    case wrongAuthData,
    case wrongDeauthData
}

class AuthManager {
    let networkManager: // injected dependency
    func deauthenticateUser(user: User) -> SignalProducer<User, AuthError> {
    // perhaps go to network:
        return SignalProducer { (observer, disposable) in
            let netOperationToken = networkManager.deauthenticate(user: user) { (user, error) in
               if let error = error {
                   observer.send(error: error)
               } else {
                   observer.send(user)
                   observer.sendCompleted()
               }
            }
            return AnyDisposable {
                networkManager.cancel(netOperationToken)
            }
        }
    }
    func authenticateUser(user: User) -> SignalProducer<User, AuthError> {
        // pretty same shit
    }
}


class AuthManager2 {
    private let innerAuthenticatedUsers = MutableProperty<[User], NoError>([])
    public let authenticatedUsers: = Property<[User], NoError>(capturing: innerAuthenticatedUsers)
    
    public func authenticate(user: User) {
        // at some point of time:
        innerAuthenticatedUsers.value = innerAuthenticatedUsers.value + [user] 
    }
}

// client code:
AuthManager2.shared.authenticatedUsers.producer.startWithValues { (authenticatedUsersArray) in
    // here will go array of authenticated users updates
}