Catching async request timeout

AsyncGetResponseFix.fs

open System
open System.IO
open System.Net

type Request = Request of WebRequest * AsyncReplyChannel<WebResponse>

let requestAgent =
    MailboxProcessor.Start <| fun inbox -> async {
            while true do
                let! (Request (req, port)) = inbox.Receive ()

                async {
                    try
                        let! resp = req.AsyncGetResponse ()
                        port.Reply resp
                    with
                    | ex -> sprintf "Exception in child %s\n%s" (ex.GetType().Name) ex.Message |> Console.WriteLine
                } |> Async.Start
        }

let getHTML url =
    async {
        try
            let req = "http://" + url |> WebRequest.Create
            try
                use! resp = requestAgent.PostAndAsyncReply ((fun chan -> Request (req, chan)), 1000)
                use str = resp.GetResponseStream ()
                use rdr = new StreamReader (str)
                return Some <| rdr.ReadToEnd ()
            with
            | :? System.TimeoutException ->
                req.Abort()
                Console.WriteLine "RequestAgent call timed out"
                return None
        with
        | ex ->
            sprintf "Exception in request %s\n%s" (ex.GetType().Name) ex.Message |> Console.WriteLine
            return None
    } |> Async.RunSynchronously;;

getHTML "www.grogogle.com"