docs: protected long[] createItemIdArray() {
          int size = operationList.size();
          long[] itemIds = new long[size];
          for (int i = 0; i < size; i++) {
              CollectionTxnOperation operation = (CollectionTxnOperation) operationList.get(i);
              itemIds[i] = CollectionTxnUtil.getItemId(operation);
          }
          return itemIds;
      }