docs: @Override
      public int delete(ObjectId id) {
          if (!isDeletable(id)) {
              return 0;
          }
  
          final DBQuery.Query query = DBQuery.is("_id", id);
          final WriteResult<IndexSetConfig, ObjectId> writeResult = collection.remove(query);
  
          final int removedEntries = writeResult.getN();
          if (removedEntries > 0) {
              final IndexSetDeletedEvent deletedEvent = IndexSetDeletedEvent.create(id.toHexString());
              clusterEventBus.post(deletedEvent);
          }
  
          return removedEntries;
      }