netris-nestri/packages/steam/HttpClientFactory.cs

using System.Net.Http.Headers;
using System.Net.Sockets;

namespace Steam;

public class HttpClientFactory
{
    public static HttpClient CreateHttpClient()
    {
        var client = new HttpClient(new SocketsHttpHandler
        {
            ConnectCallback = IPv4ConnectAsync
        });

        var assemblyVersion = typeof(HttpClientFactory).Assembly.GetName().Version?.ToString(fieldCount: 3);
        client.DefaultRequestHeaders.UserAgent.Add(new ProductInfoHeaderValue("DepotDownloader", assemblyVersion));

        return client;
    }

    static async ValueTask<Stream> IPv4ConnectAsync(SocketsHttpConnectionContext context, CancellationToken cancellationToken)
    {
        // By default, we create dual-mode sockets:
        // Socket socket = new Socket(SocketType.Stream, ProtocolType.Tcp);

        var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
        {
            NoDelay = true
        };

        try
        {
            await socket.ConnectAsync(context.DnsEndPoint, cancellationToken).ConfigureAwait(false);
            return new NetworkStream(socket, ownsSocket: true);
        }
        catch
        {
            socket.Dispose();
            throw;
        }
    }
}