Old async

oldAsync.fs

let asyncDownload1 (url : string) =
    let req = HttpWebRequest.Create url
    req.BeginGetResponse(fun ar ->
            use resp = req.EndGetResponse(ar)
            use stream = resp.GetResponseStream()
            let result = ref [||]
            let buffer = Array.zeroCreate 8192 : byte []
            let rec readAll () =                
                stream.BeginRead(buffer, 0, buffer.Length, fun ar2 ->
                        match stream.EndRead ar2 with
                        | 0 -> ()
                        | n ->
                            result := Array.concat [!result; buffer.[0..(n-1)]]
                            readAll()
                    , null)
            readAll()
        , null)