anchor.diff:                  let sender = mailbox.Sender()
                   match state', message with
                   | Some (_, userMonitor), Connect(x,y) ->
  +                    printfn "Connect in server: %A" userMonitor
                       let user = userMonitor.Connect x y
  +                    printfn "Result in user %A" user
                       sender <! user
                   | Some (roomMonitor, _), GetRoomList ->
                       let roomList = roomMonitor.GetRoomList()
  
positive.code: 
      type RoomActorState = {RoomName: RoomName; ConnectedUsers: Map<UserName,UserConnection>}
      let roomActor initState (mailbox:Actor<RoomMessage>) =
          let notifyUsers state notification =
              let userActors = state.ConnectedUsers |> Map.toList |> List.map snd
              printfn "Users in room: %A" userActors
              userActors |> List.iter (fun userActor -> userActor.Notify notification)
  
  
negative.code:             let result = chatServer.CreateRoom roomName
              printfn "Create room result %A" result
          let joinRoom roomName = user.JoinRoom roomName
          let say (message, roomName) = user.Say message roomName
          let getRoomList() = chatServer.GetRoomList()
          {
              CreateRoom = createRoom
  