anchor.diff:  -record(session, {
     id = undefined,
     pid = undefined,
  +  ref = undefined,
     details = undefined,
     requestId = 1,
     goodbye_sent = false,
  
positive.code: create_session(Pid,Details,#state{sess=Sessions}=State) ->
    Id = gen_id(),
    Ref = monitor(process,Pid),
    case ets:insert_new(Sessions,[#session{id=Id,pid=Pid,details=Details},
                                  #ref_session{ref=Ref,session_id=Id},
                                  #pid_session{pid=Pid,session_id=Id}]) of
      true ->
  
negative.code:       end,
    {reply,Reply,State};
  
  handle_call({remove_session,_Reason},{Pid,_Ref},State) ->
    Session = get_session_from_pid(Pid,State),
    remove_given_session(Session,State),
    {reply,shutdown,State};
  handle_call(_Msg,_From,State) ->
     {reply,shutdown,State}.
  
  