anchor.diff:           passed_state            = ?required(state, passed_state)
                                          :: none | passed_state(),
            num_possible_executions = ?required(state, passed_state)
  -                                       :: pos_integer()
  +                                       :: pos_integer(),
  +         callback_on_deliver     = ?required(state, callback_on_deliver)
  +                                       :: callback_on_deliver()
           }).
   
   -type state_t() :: #state{}.
  +
   -spec start() -> ok.
   start() -> start(default).
   
  
positive.code: -export([start/0, start/1, start/2, stop/0]).
  -export([start_deliver/0, start_deliver/1]).
  -export([get_infos/0, get_infos/1]).
  -export([cleanup/0, cleanup/1]).
  
  %% report messages from other modules
  
negative.code:             msg_delay_queues = [],
              status = stopped,
              passed_state = passed_state_new(TraceId, {proto_sched, Logger}),
              num_possible_executions = 1,
              callback_on_deliver = fun(_From, _To, _Msg) -> ok end
            }.
  
  %% @doc Sends out all messages remaining in queues
  