used by 'Lessons learned from handling JWT on mobile' article on Medium

token_refresh_snippet_2.swift

class AuthorizationValueProvider {

    private let authenticationInfoStore: AuthenticationInfoStorage
    private let tokenRefreshAPI: TokenRefreshing
    
    private let queue = DispatchQueue(label: <#label#>, qos: .userInteractive)
    private let semaphore = DispatchSemaphore(value: 1)

    init(tokenRefreshAPI: TokenRefreshing,
         authenticationInfoStore: AuthenticationInfoStorage) {
        self.tokenRefreshAPI = tokenRefreshAPI
        self.authenticationInfoStore = authenticationInfoStore
    }

    func getValidUserAuthorization(completion: @escaping (Result<AuthorizationValue, Error>) -> Void) {
        queue.async {
            self.getValidUserAuthorizationInMutualExclusion(completion: completion)
        }
    }
}