ConnectCallback.cs

async ValueTask<Stream> ConnectAsync(SocketsHttpConnectionContext context, CancellationToken cancellationToken)
{
    var socket = new Socket(SocketType.Stream, ProtocolType.Tcp) { NoDelay = true };
    try
    {
        await socket.ConnectAsync(context.DnsEndPoint, cancellationToken);
        socket.SetFoo(bar);
        return new NetworkStream(socket, ownsSocket: true);
    }
    catch
    {
        socket.Dispose();
        throw;
    }
}

async ValueTask<Stream> ConnectAsync(SocketsHttpConnectionContext context, CancellationToken cancellationToken)
{
    var networkStream = await context.DefaultConnectAsync(cancellationToken);
    networkStream.Socket.SetFoo(bar);
    return networkStream;
}