Delayed computation example

user.fs

 
        msg {
            let! xn = ApiSubmit ( API.GetWorker )
            match xn with
            //match! User.Get with
            | Ok data ->
                yield StorageSave ( DataKey.User, data )
            | Error (e: FableUtil.FetchUtil.Response) ->
                yield ApplicationError <| string e.Status + " " + e.StatusText

            match loadUser () with 
            | Some user ->
                yield user |> UserIndex.Message.Load |> PageMsg.UserIndex |> PageMessage
            | _ -> ()
        }
        
        
        //somewhere else in a global message loop
        | Continuation ( ( APICall apiModel ), next ), _ ->
        model
        , Cmd.OfPromise.either API.submit apiModel
            ( fun _ -> next )
            ( fun e -> alert "Erro" e.Message )