anchor.diff:  %See if we have work. If we do, dispatch.
   %If we don't, stay in at_rest.
   %% @private
  --spec at_rest({call, pid()} | cast | info, term(), statedata()) ->
  +-spec at_rest({call, gen_statem:from()} | cast | info, term(), statedata()) ->
       keep_state_and_data |
       {keep_state, statedata()} |
       {next_state, atom(), statedata(), timeout()}.
  
positive.code:     enqueue_work_or_stop(StateName, Event, From, StateData, infinity).
  
  %% @private
  -spec enqueue_work_or_stop(atom(), term(), pid(), statedata(), timeout()) ->
      keep_state_and_data |
      {keep_state, statedata()}.
  enqueue_work_or_stop(_StateName, Event, From, StateData, Timeout) ->
      case create_work(Event, From) of
          {ok, Work} ->
  
negative.code:     handle_info(Event, at_rest, StateData).
  
  %% @private
  -spec wait_response({call, gen_statem:from()} | cast | info, term(), statedata()) ->
      keep_state_and_data |
      {keep_state, statedata()} |
      {stop, {error, any()}, atom(), statedata()} |
  