@Override
 public void stop() throws IOException {
   if (partitionWriters != null) {
     try {
       for (DiskBlockObjectWriter writer : partitionWriters) {
         // This method explicitly does _not_ throw exceptions:
         File file = writer.revertPartialWritesAndClose();
         if (!file.delete()) {
           logger.error("Error while deleting file {}", file.getAbsolutePath());
         }
       }
     } finally {
       partitionWriters = null;
     }
   }
 }