Sending an email, F#

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open System
    open System.Net.Mail
    // open System.Configuration
    let server = "smtp.myserver.com" // ConfigurationManager.AppSettings.["mailserver"]
    let sender = "nospam@mydomain.com" // ConfigurationManager.AppSettings.["mailsender"]
    let password = "abc123" // ConfigurationManager.AppSettings.["mailpassword"] |> my-decrypt
    let port = 587
    let sendMailMessage email name topic msg =
        let msg = 
            new MailMessage(
                sender, email, topic, "Dear " + name + ", <br/><br/>\r\n\r\n" + msg)
        msg.IsBodyHtml <- true
        let client = new SmtpClient(server, port)
        client.EnableSsl <- true
        client.Credentials <- System.Net.NetworkCredential(sender, password)
        client.SendCompleted |> Observable.add(fun e -> 
            let msg = e.UserState :?> MailMessage
            if e.Cancelled then
                ("Mail message cancelled:\r\n" + msg.Subject) |> Console.WriteLine
            if e.Error <> null then
                ("Sending mail failed for message:\r\n" + msg.Subject + 
                    ", reason:\r\n" + e.Error.ToString()) |> Console.WriteLine
            if msg<>Unchecked.defaultof<MailMessage> then msg.Dispose()
            if client<>Unchecked.defaultof<SmtpClient> then client.Dispose()
        )
        // Maybe some System.Threading.Thread.Sleep to prevent mail-server hammering
        client.SendAsync(msg, msg)

Show compiler warnings [ + ] Show input
Compilation time: 3.08 sec, absolute running time: 0.18 sec, cpu time: 0.13 sec, memory peak: 5 Mb, absolute service time: 3,27 sec