C# vs F# 0MQ sync REP server

gistfile1.txt

public class Server
{
    private readonly NetMQContext _context;
    private readonly string _id;

    public Server(NetMQContext context, string id)
    {
        _context = context;
        _id = id;
    }

    public Task Start(CancellationToken token, string address)
    {
        var ready = new TaskCompletionSource<bool>();
        Task.Factory.StartNew(() => start(token, address, ready), token, TaskCreationOptions.LongRunning, TaskScheduler.Default);
        return ready.Task;
    }

    private void start(CancellationToken token, string address, TaskCompletionSource<bool> ready)
    {
        using (var socket = _context.CreateResponseSocket())
        {
            socket.Bind(address);
            ready.SetResult(true);
            while (token.IsCancellationRequested == false)
            {
                var bytes = socket.Receive();
                var sender = Encoding.ASCII.GetString(bytes);
                Console.WriteLine("[{0}] Received request from {1}", _id, sender);
                Task.Delay(TimeSpan.FromSeconds(3), token).Wait(token);
                var message = string.Format("{0} says {1}.", _id, DateTime.Now);
                socket.Send(Encoding.ASCII.GetBytes(message));
            }
        }
    }
}

gistfile2.txt

let server (ctx:NetMQContext, address, id, token:CancellationToken) = 
    let doWork (ready:Tasks.TaskCompletionSource<bool>) =
        async {
            use socket = ctx.CreateResponseSocket()
            socket.Bind address
            ready.SetResult true
            while token.IsCancellationRequested = false do
                let sender = 
                    socket.Receive()
                    |> System.Text.Encoding.ASCII.GetString 
                do printfn "[%s] Got request from %s" id sender
                Tasks.Task.Delay(2000, token).Wait token
                DateTime.Now.ToString()
                |> System.Text.Encoding.ASCII.GetBytes
                |> socket.Send
        }    
    let ready = new Tasks.TaskCompletionSource<bool>()
    doWork ready
    |> fun x -> Async.Start(x, token) 
    ready.Task