using System;

using System.Linq;

using System.Threading.Tasks;

using System.Net.Http;

using Microsoft.Extensions.DependencyInjection;

public class Program

{

    private const string ClientName = "TestClient";

    private const string HeaderKey = "AuthToken";

    public static async Task Main()

    {

        var collection = new ServiceCollection();

        collection.AddHttpClient(ClientName, (sp, client) =>

        {

            client.DefaultRequestHeaders.Add(HeaderKey, GetToken());

        });

        var provider = collection.BuildServiceProvider();

        //Simulate retry

        for(int i = 0; i < 5; i++)

        {

            Test(provider);

            await Task.Delay(Random.Shared.Next(1000));

        }

    }

    public static void Test(IServiceProvider sp)

    {

        var factory = sp.GetRequiredService<IHttpClientFactory>();

        var client = factory.CreateClient(ClientName);

        var token = client.DefaultRequestHeaders.GetValues(HeaderKey).First();

        Console.WriteLine($"Token: {token}");

        //Simulate token refresh

        client.DefaultRequestHeaders.Remove(HeaderKey);

        client.DefaultRequestHeaders.Add(HeaderKey, GetToken());

    }

    private static string GetToken() => DateTime.UtcNow.TimeOfDay.ToString();

}