code: @Override
      public void accum(FgModel model, int i, Accumulator ac) {
          try {
              accumWithException(model, i, ac);
          } catch(Throwable t) {
              log.error("Skipping example " + i + " due to throwable: " + t.getMessage());
              t.printStackTrace();
          }
      }
docs: Assumed by caller to be threadsafe.