F# akka fsm

open System
open Akka.FSharp

type PersonName = PersonName of string
type Person = {Name:PersonName; Age:int}
type ActorMessage =
    | BeginProcess of PersonName
    | PersonDetails of Person

[<EntryPoint>]
let main argv =
    let system = System.create "my-system" (Configuration.defaultConfig())

    let detailsActor =
        spawn system "my-child-actor" <| actorOf2
            (fun mailbox name ->
                // ... Normally we have some query here for the user ...
                // But we are just going to Tell the sender actor about a Person
                mailbox.Sender() <! (PersonDetails {Name=name; Age=99}) )

    let rootActor =
        spawn system "my-parent-actor"
        <| fun mailbox ->
            let rec idle () =
                actor {
                    let! message = mailbox.Receive()
                    match message with
                    | BeginProcess name ->
                        detailsActor <! name
                        return! awaitingdetails name
                    | _ ->
                        return! idle ()
                }
            and awaitingdetails name =
                actor {
                    let! message = mailbox.Receive()
                    match message with
                    | PersonDetails person ->
                        printfn "Received person :: %A" person
                        mailbox.UnstashAll()
                        return! idle ()
                    | _ ->
                        mailbox.Stash()
                        return! awaitingdetails name
                }

            idle ()