In fetchUsers method, it has a guard check first, so if users is not empty, aka Core Data has users data, the code will return and it will never do the network fetch request again.

My problem is that if JSON data from server have some update in the future, our code would not get it because the users would never be empty after it get the value from the first network call.

    func fetchUsers() async {
        guard users.isEmpty else { return }

        do {
            let url = URL(string: "https://www.hackingwithswift.com/samples/friendface.json")!
            let (data, _) = try await URLSession.shared.data(from: url)

            let decoder = JSONDecoder()
            decoder.dateDecodingStrategy = .iso8601
            let users = try decoder.decode([User].self, from: data)
            await MainActor.run {
                updateCache(with: users)
            }
        } catch {
            print("Download failed.")
        }
    }