Program.cs

using System;
using System.Threading.Tasks;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace HttpClientConsoleSample
{
    class Program
    {
        static async Task Main(string[] args)
        {
            var builder = new HostBuilder()
                .ConfigureServices((hostContext, services) =>
                {
                    services.AddHttpClient();
                    services.AddTransient<IBlog, Blog>();
                }).UseConsoleLifetime();

            var host = builder.Build();

            using (var serviceScope = host.Services.CreateScope())
            {
                var services = serviceScope.ServiceProvider;
                try
                {
                    var blogService = services.GetRequiredService<IBlog>();
                    var article = await blogService.GetArticle("2020/02/aspnet-core-provider-mask-api.html");

                    // output first 1000 words.
                    Console.WriteLine(article.Substring(0, 1000));
                    Console.Read();
                }
                catch (Exception ex)
                {
                    var logger = services.GetRequiredService<ILogger<Program>>();
                    logger.LogError(ex, "An error occurred.");
                }
            }
        }
    }
}