anchor.diff:          {fail, not_found} ->
               timer:sleep(randoms:rand_uniform(1, erlang:max(2, 10 * Aborts + 1))),
               increment_iter(Key, Iterations, Aborts + 1);
  -        X -> log:log(warn, "~p", [X])
  -    end.
  -
  --spec increment_with_histo_iter(histogram:histogram(), string(), integer(), non_neg_integer()) -> any().
  +        X ->
  +            log:log(warn, "bench_fun:increment_iter unexpected return: ~p", [X]),
  +            increment_iter(Key, Iterations, Aborts +1)
  +    end.
  +
  +-spec increment_with_histo_iter(histogram:histogram(), string(), integer(), non_neg_integer()) -> {histogram:histogram(), non_neg_integer()}.
   increment_with_histo_iter(H, _Key, 0, Aborts) ->
       {Aborts, H};
   increment_with_histo_iter(H, Key, Iterations, Aborts) ->
  
positive.code:         {fail, not_found} ->
              timer:sleep(randoms:rand_uniform(1, erlang:max(2, 10 * Aborts + 1))),
              increment_with_histo_iter(H, Key, Iterations, Aborts + 1);
          X -> log:log(warn, "~p", [X])
      end.
  
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
negative.code:         Fail -> Fail
      end.
  
  -spec increment_iter(string(), integer(), non_neg_integer()) -> non_neg_integer().
  increment_iter(_Key, 0, Aborts) ->
      Aborts;
  increment_iter(Key, Iterations, Aborts) ->
  