anchor.diff:  -ifdef(TEST).
   
   next_corr_id_test() ->
  -  ?assertEqual(0, next_corr_id((1 bsl 31) - 1)).
  +  CorrId = (1 bsl 31) - 1,
  +  Req = #requests{corr_id = CorrId},
  +  {CorrId, NewReq} = add(Req, self(), api_key),
  +  ?assertEqual(0, get_corr_id(NewReq)).
   
   -endif. % TEST
   
  
positive.code:         , del/2
          , get_api_key/2
          , get_caller/2
          ]).
  
  -export_type([requests/0]).
  
negative.code:   {Caller, _ApiKey} = gb_trees:get(CorrId, Sent),
    Caller.
  
  
  %% @doc Get the correction to be sent for the next request.
  -spec get_corr_id(requests()) -> corr_id().
  get_corr_id(#requests{ corr_id = CorrId }) ->
    CorrId.
  
  %%%_* Internal functions =======================================================
  
  next_corr_id(?MAX_CORR_ID) -> 0;
  