using System;

using System.Collections.Generic;

using System.Net.Http;

using Microsoft.Extensions.DependencyInjection;

public class Program

{

    public static void Main()

    {

        // Setup DI

        var serviceCollection = new ServiceCollection();

        serviceCollection

            .AddHttpClient<ITypedClient, TypedClientA>(

                httpClient => {

                    httpClient.BaseAddress = new Uri("http://fake.local/address/1");

                    httpClient.DefaultRequestHeaders.Add("Accept", "application/json");

                    httpClient.DefaultRequestHeaders.Add("caller", "caller");

                    httpClient.DefaultRequestHeaders.Add("actor", nameof(TypedClientA));

                });

        serviceCollection

            .AddHttpClient<ITypedClient, TypedClientB>(

                httpClient => {

                    httpClient.BaseAddress = new Uri("http://fake.local/address/2");

                    httpClient.DefaultRequestHeaders.Add("Accept", "application/json");

                    httpClient.DefaultRequestHeaders.Add("caller", "caller");

                    httpClient.DefaultRequestHeaders.Add("actor", nameof(TypedClientB));                    

                });

        var serviceProvider = serviceCollection.BuildServiceProvider();

        var allTypedClients = serviceProvider.GetServices<ITypedClient>();

        foreach (var tc in allTypedClients)

        {

            tc.Print(); 

        }

    }

    public interface ITypedClient

    {

        void Print();

    }

    public class TypedClientA : ITypedClient

    {

        private readonly HttpClient _httpClient;

        public TypedClientA(HttpClient httpClient)

        {

            _httpClient = httpClient;

        }

        public void Print()

        {

            Console.WriteLine(nameof(TypedClientA));

            Console.WriteLine(_httpClient.BaseAddress);

            Console.WriteLine(_httpClient.DefaultRequestHeaders.ToString());

        }

    }

    public class TypedClientB : ITypedClient

    {

        private readonly HttpClient _httpClient;

        public TypedClientB(HttpClient httpClient)

        {

            _httpClient = httpClient;

        }

        public void Print()

        {

            Console.WriteLine(nameof(TypedClientB));

            Console.WriteLine(_httpClient.BaseAddress);

            Console.WriteLine(_httpClient.DefaultRequestHeaders.ToString());

        }

    }

}