anchor.diff:    NewClockMap =
       case Special of
         {new, SpawnedPid} ->
  -        dict:store(SpawnedPid, Clock, ClockMap);
  +        clock_map_store(SpawnedPid, Clock, ClockMap);
         {message, #message_event{message = #message{id = Id}}} ->
  -        dict:store({Id, sent}, Clock, ClockMap);
  +        clock_map_store({Id, sent}, Clock, ClockMap);
         _ -> ClockMap
       end,
     add_new_and_messages(Rest, Clock, NewClockMap).
  
positive.code: -type clock_map()           :: dict().
  -type message_event_queue() :: queue().
  -else.
  -type clock_map()           :: dict:dict(pid(), vector_clock()).
  -type message_event_queue() :: queue:queue(#message_event{}).
  -endif.
  
  
negative.code:             true -> independent;
              false -> IrreversibleClock
            end,
          BaseNewClockMap = clock_map_store(state, StateClock, ClockMap),
          %% The actor's clock should be added to anything else stemming
          %% from the step (spawns, sends and deliveries)
          NewClockMap =
            add_new_and_messages(Special, ActorNewClock, BaseNewClockMap),
          FinalClockMap = clock_map_store(Actor, ActorNewClock, NewClockMap),
          TraceState#trace_state{clock_map = FinalClockMap}
      end,
    assign_happens_before(Later, [NewTraceState|RevLate], RevEarly, State, Mode).
  