anchor.diff:      state_start(),
       %% Save empty replay state for the first run.
       {init_state, InitState} = lists:keyfind(init_state, 1, Options),
  -    state_save(InitState),
  +    state_save({InitState, []}),
       PreBound =
           case lists:keyfind(preb, 1, Options) of
               {preb, inf} -> ?INFINITY;
  
positive.code: %% If no states available, return 'no_state'.
  state_load() ->
      case get(?NT_STATE1) of
          [State|Rest] ->
              put(?NT_STATE1, Rest),
              state:pack(State);
          [] -> no_state
      end.
  
  
negative.code:         false -> {NewContext, {Rest, W}}
      end.
  
  insert_states(_State, {[], _}) ->
      ok;
  insert_states(State, {Lids, current}) ->
      state_save({State, Lids});
  insert_states(State, {Lids, next}) ->
      state_save_next({State, Lids}).
  
  %% Run process Lid in context Context until it encounters a preemption point.
  run(#context{current = Lid, state = State} = Context) ->
  