gistfile1.fs

type IdGenerator () =
    let agent = MailboxProcessor<AsyncReplyChannel<int>>.Start(fun inbox ->
        let rec loop c = async {
            let! rc = inbox.Receive ()
            rc.Reply (c + 1)
            return! loop (c + 1) }
        loop 0)
        
    member this.Next () =
        agent.PostAndReply(fun rc -> rc)
        
        
let idGen = IdGenerator ()

idGen.Next()