namespace MyApp
{
    public class Startup
    {
        public void Configure(IApplicationBuilder app, ILoggerFactory loggerFactory)
        {
            app.Run(async context => {
                context.Response.StatusCode = 200;
                await context.Response.WriteAsync("test");
            });
        }
    }

    public static class Program
    {
        public static void Main(string[] args)
        {
            var app = WebHost.CreateDefaultBuilder(args)
                .UseKestrel(options => {
                    options.Listen(IPAddress.Loopback, 5000);
                    options.AllowSynchronousIO = false;
                })
                .UseStartup<Startup>()
                .Build();
            app.Run();
        }
    }
}

$ dotnet run

$ ab -p test.json -n 20000 -c 100 http://127.0.0.1:5000/