using System;

using System.Threading.Tasks;

using System.Net.Sockets;

using System.Text;

using System.Text.Encodings;

using System.IO;

using System.Linq;

using Nito.AsyncEx;

​

public class Program

{

    public static async Task Main()

    {

        var ipAddress = "1.1.1.1";

        var port = 80;

​

        var client = new TcpClient(ipAddress, port);

        var stream = client.GetStream();

        await stream.WriteAsync(Encoding.UTF8.GetBytes("GET / HTTP/1.1\r\nHost: {ipAddress}\r\nConnection: close\r\n\r\n"));

​

        var buffers = Enumerable.Range(0, 16).Select(_ => new byte[4096]);

        var reset = new AsyncManualResetEvent(false);

        var task = buffers.Select(buffer => ReadAsync(reset, stream, buffer)).WhenAll().ContinueWith(task => task.Result.ToList());

        reset.Set();

        var lengths = await task;

        foreach (var length in lengths)

            Console.WriteLine($"length: {length}");

    }

    public static async Task<int> ReadAsync(AsyncManualResetEvent reset, Stream stream, Memory<byte> buffer)

    {

        await reset.WaitAsync();

        return await stream.ReadAsync(buffer);

    }

}