C# code to quickly send requests to a HTTP server. Can send over ~1500 requests per second to a remote server.

fastRequests.cs

using System.Net;
using System.Net.Http.Headers;
using System.Text;

namespace fastRequests
{
    internal static class Program
    {
        private const string Host = "example.com";
        private const string Url = "https://example.com/";
        private const string Ip = "1.2.3.4";
        private static readonly HttpMethod TaskType = HttpMethod.Post;

        private static readonly HttpContent Content = new StringContent(
            "say=Hello",
            Encoding.UTF8,
            "application/x-www-form-urlencoded"
        );

        private const int ThreadsCount = 8;
        private const int ParallelCount = 32;

        private static readonly UriBuilder WebBuilder = new(Url)
        {
            Host = Ip
        };

        private static readonly HttpClient Client = new(new HttpClientHandler
        {
            UseCookies = false,
            UseProxy = false,
            MaxConnectionsPerServer = int.MaxValue,
            CheckCertificateRevocationList = false,
            AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate
        })
        {
            DefaultRequestHeaders =
            {
                Accept = { new MediaTypeWithQualityHeaderValue("text/html") },
                Host = Host,
                Referrer = WebBuilder.Uri
            }
        };

        private static ulong _requestsCount;

        private static void Counter()
        {
            var lastCount = 0ul;

            var watch = new System.Diagnostics.Stopwatch();
            watch.Start();

            while (true)
            {
                Thread.Sleep(10000);

                var elapsedMs = watch.ElapsedMilliseconds;
                watch.Restart();
                var currentCount = Interlocked.Read(ref _requestsCount);

                Console.WriteLine(
                    $"Tasks per second: {(((double)(currentCount - lastCount)) / elapsedMs) * 1000,10:0.000} | Total: {currentCount,15}");

                lastCount = currentCount;
            }
        }

        private static void Requester()
        {
            var tasks = new Task<HttpResponseMessage>[ParallelCount];
            while (true)
            {
                for (var i = 0; i < ParallelCount; i++)
                {
                    tasks[i] = Client.SendAsync(
                        new(TaskType, WebBuilder.Uri)
                        {
                            Content = Content
                        },
                        HttpCompletionOption.ResponseContentRead,
                        CancellationToken.None
                    );
                }

                Task.WaitAll(tasks);
                Interlocked.Add(ref _requestsCount, ParallelCount);
            }
        }

        private static void Main()
        {
            new Thread(Counter).Start();
            Parallel.For(0, ThreadsCount, _ => Requester());
        }
    }
}