very simple signalr server + client

Clients.cs

    class Program
    {
        static async Task Main(string[] args)
        {
            var connection = new HubConnectionBuilder().WithUrl("http://localhost:19715/chat")
                .Build();
            await connection.StartAsync();

            var receiveCounter = 0;
            var isReceiver = args.Length < 1 || args[0].ToLower() != "sender";
            if (isReceiver)
            {
                var stopWatch = new Stopwatch();
                connection.On<int>("Send",
                    (id) =>
                    {
                        if (!stopWatch.IsRunning)
                        {
                            stopWatch.Start();
                        }
                        
                        receiveCounter++;
                        if (receiveCounter % 1000 == 0)
                        {
                            Console.WriteLine($"Receiving {receiveCounter} ({stopWatch.Elapsed})");
                        }
                    });
                if (receiveCounter >= 10000000)
                {
                    Console.WriteLine($"It took {stopWatch.Elapsed} to receive {receiveCounter} values");
                }

                Console.ReadLine();
                return;
            }

            for (var i = 0; i < 10000000; i++)
            {
                if (i % 1000 == 0)
                {
                    Console.WriteLine($"Sending {i}");
                }
                await connection.InvokeAsync("Send", i);
            }

            Console.ReadLine();
        }
    }

Server.cs

public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddSignalR().AddMessagePackProtocol();
        }

        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            app.UseSignalR(routes => { routes.MapHub<Chat>("/chat"); });

            app.Run(async context => { await context.Response.WriteAsync("Hello world!"); });
        }
    }
    
    public class Chat : Hub
    {
        public Task Send(int id)
        {
            return this.Clients.All.SendAsync("Send", id);
        }
    }