anchor.diff:  open Akka.Actor
   open ComposeIt.Akka.FSharp.Extensions.Lifecycle
   open System
  +open System.Threading.Tasks
   open Xunit
   
   let equals (expected: 'a) (value: 'a) = Assert.Equal<'a>(expected, value) 
  
positive.code: 
      use system = System.create "testSystem" (Configuration.load())
      let actor = 
          spawnOvrd system "actor" 
          <| actorOf (namePrinter "No one")
          <| {defOvrd with PreStart = preStart}
      actor <! MyName "Tomasz"
      actor <! MyName "Marcel"
      actor <! Print
      system.Terminate() |> ignore
      system.WhenTerminated.Wait(TimeSpan.FromSeconds(2.)) |> ignore
      (!preStartCalled, answer) |> equals (true, ref "Last name was Marcel?")
negative.code: [<Fact>]
  let ``can change behaviour with become`` () =
      
      let answer = ref "no one"
  
      let rec namePrinter lastName = function
          | Print -> answer := sprintf "Last name was %s?" lastName
  