code: private void deleteSpillFiles() {
      for (UnsafeSorterSpillWriter spill : spillWriters) {
        File file = spill.getFile();
        if (file != null && file.exists()) {
          if (!file.delete()) {
            logger.error("Was unable to delete spill file {}", file.getAbsolutePath());
          }
        }
      }
    }
docs: Deletes any spill files created by this sorter.