code: @Deprecated
      public List<Cursor> parallelScan(final ParallelScanOptions options) {
          List<Cursor> cursors = new ArrayList<Cursor>();
          ParallelCollectionScanOperation<DBObject> operation = new ParallelCollectionScanOperation<DBObject>(getNamespace(),
                                                                                                              options.getNumCursors(),
                                                                                                              objectCodec)
                                                                    .batchSize(options.getBatchSize()).retryReads(retryReads);
          ReadPreference readPreferenceFromOptions = options.getReadPreference();
          List<BatchCursor<DBObject>> mongoCursors = executor.execute(operation,
                                                                      readPreferenceFromOptions != null ? readPreferenceFromOptions
                                                                                                          : getReadPreference(),
                  getReadConcern());
  
          for (BatchCursor<DBObject> mongoCursor : mongoCursors) {
              cursors.add(new MongoCursorAdapter(new MongoBatchCursorAdapter<DBObject>(mongoCursor)));
          }
          return cursors;
      }
docs: <p>Return a list of cursors over the collection that can be used to scan it in parallel.</p>
  
  <p>Note: As of MongoDB 2.6, this method will work against a mongod, but not a mongos. </p>
  
  @param options the parallel scan options
  @return a list of cursors, whose size may be less than the number requested
  @mongodb.driver.manual reference/command/parallelCollectionScan/ Parallel Collection Scan
  @mongodb.server.release 2.6
  @since 2.12
  @deprecated the parallelCollectionScan command will be removed in MongoDB 4.2