simple example using an F# MailboxProcessor

MailboxProcessor.fsx

type Msg =
    | Msg of string
    | Done of AsyncReplyChannel<int>

let printerAgent = MailboxProcessor.Start(fun inbox->

    // the message processing function
    let rec messageLoop() = async{
        let! msg = inbox.Receive()
        match msg with
        | Msg s -> printfn "message is: %s" s
        | Done rc -> rc.Reply(0)
        return! messageLoop()
        }

    // start the loop
    messageLoop()
    )


let xs = List.map (fun n -> sprintf "hello %d" n) [1..30]
for s in xs do
    printerAgent.Post(Msg s)

printerAgent.PostAndReply(fun rc -> Done rc)
|> printfn "exit code: %d"