Akka.Persistence.FSharp aggregate/view cooperation

Sample.fs

open System
open Akka
open Akka.Actor
open Akka.FSharp
open Akka.Persistence.FSharp

let system = System.create "persistence-sys" <| Configuration.parse """
    akka {    
      persistence {
        journal {
          plugin = "akka.persistence.journal.sqlite"
          sqlite {
            class = "Akka.Persistence.Sqlite.Journal.SqliteJournal, Akka.Persistence.Sqlite"
            connection-string = "Data Source=.\\store.db;Version=3;"
            auto-initialize = true
          }
        }
        snapshot-store {
          plugin = "akka.persistence.snapshot-store.sqlite"
          sqlite {
            class = "Akka.Persistence.Sqlite.Snapshot.SqliteSnapshotStore, Akka.Persistence.Sqlite"
            connection-string = "Data Source=.\\store.db;Version=3;"
            auto-initialize = true
          }
        }
      }
    }
    """
let j = Akka.Persistence.Persistence.Instance.Apply(system).JournalFor(null)

let update state e = e::state

let apply _ = update

let exec (mailbox: Eventsourced<_,_,_>) state cmd = 
    match cmd with
    | "print" -> printf "State is: %A\n" state          
    | s       -> mailbox.PersistEvent (update state) [s]     

let pref = 
    spawnPersist system "p1" {  
        state = []              
        apply = apply           
        exec = exec             
    } []    

pref <! "a"
pref <! "b"
pref <! "c"
let viewApply (mailbox: View<_,_>) state = function
    | "print" -> 
        mailbox.Sender() <! state
        state
    | e -> state + e

let vref =
    spawnView system "v1" "p1" {
        state = ""
        apply = viewApply
    } []

async {
    let! resp = vref <? "print"
    printfn "View is: %s" resp
} |> Async.RunSynchronously

Console.ReadLine()