code: MongoCollection<BsonDocument> getUndoCollection(final MongoNamespace namespace) {
      return localClient
          .getDatabase(String.format("sync_undo_%s", namespace.getDatabaseName()))
          .getCollection(namespace.getCollectionName(), BsonDocument.class)
          .withCodecRegistry(MongoClientSettings.getDefaultCodecRegistry());
    }
docs: Returns the undo collection representing the given namespace for recording documents that
  may need to be reverted after a system failure.
  
  @param namespace the namespace referring to the undo collection.
  @return the undo collection representing the given namespace for recording documents that
  may need to be reverted after a system failure.