anchor.diff:        Event = #event{label = make_ref()},
         NewState = State#scheduler_state{bound_consumed = 0},
         get_next_event(Event, System ++ AvailableActors, NewState);
  -    [{#event{actor = Actor, label = Label} = Event, N, _}|_] ->
  +    [#backtrack_entry{
  +        event = #event{actor = Actor, label = Label} = Event,
  +        origin = N}|_] ->
         ?log(Logger, ?ldebug,"By: ~p~n", [N]),
         false = lists:member(Actor, Sleeping),
         BoundConsumed =
  
positive.code:   {NewLastWakeupTree, NextWakeupTree} =
      case WakeupTree of
        [] -> {[], []};
        [{_, _, NWT}|Rest] -> {Rest, NWT}
      end,
    NewLastDone = [Event|Done],
    NewSchedulingBound =
  
negative.code:         false ->
            case insert_wakeup(Deeper, NewNotDep, Exploring) of
              skip -> skip;
              NewTree ->
                Entry =
                  #backtrack_entry{
                     event = Event,
                     origin = M,
                     wakeup_tree = NewTree},
                [Entry|Rest]
            end
        end
    end.
  