code: @Override
      public void add(Difference difference) {
          differenceCount += 1;
          if(differenceCount <= DIFFERENCE_COUNT_MAX) {
              list.add(difference);
          }
          try {
              writer.write(difference.toString());
          } catch (IOException e) {
              throw new DiffException("Failed to write difference to report file", e);
          }
      }
docs: Add a new difference to the report
  @param difference {@code Difference}