@Override
  public int serialize(byte[] stream, int offset, UUID ownerUuid) {
    for (Map.Entry<OIdentifiable, OModifiableInteger> entry : newEntries.entrySet()) {
      OIdentifiable identifiable = entry.getKey();
      assert identifiable instanceof ORecord;
      Change c = changes.get(identifiable);

      final int delta = entry.getValue().intValue();
      if (c == null) changes.put(identifiable, new DiffChange(delta));
      else c.applyDiff(delta);
    }
    newEntries.clear();

    final ORecordSerializationContext context;
    boolean remoteMode =
        ODatabaseRecordThreadLocal.INSTANCE.get().getStorage() instanceof OStorageProxy;
    if (remoteMode) {
      context = null;
    } else context = ORecordSerializationContext.getContext();

    // make sure that we really save underlying record.
    if (collectionPointer == null) {
      if (context != null) {
        final int clusterId = getHighLevelDocClusterId();
        assert clusterId > -1;
        collectionPointer =
            ODatabaseRecordThreadLocal.INSTANCE
                .get()
                .getSbTreeCollectionManager()
                .createSBTree(clusterId, ownerUuid);
      }
    }

    OBonsaiCollectionPointer collectionPointer;
    if (this.collectionPointer != null) collectionPointer = this.collectionPointer;
    else {
      collectionPointer = OBonsaiCollectionPointer.INVALID;
    }

    OLongSerializer.INSTANCE.serializeLiteral(collectionPointer.getFileId(), stream, offset);
    offset += OLongSerializer.LONG_SIZE;

    OBonsaiBucketPointer rootPointer = collectionPointer.getRootPointer();
    OLongSerializer.INSTANCE.serializeLiteral(rootPointer.getPageIndex(), stream, offset);
    offset += OLongSerializer.LONG_SIZE;

    OIntegerSerializer.INSTANCE.serializeLiteral(rootPointer.getPageOffset(), stream, offset);
    offset += OIntegerSerializer.INT_SIZE;

    // Keep this section for binary compatibility with versions older then 1.7.5
    OIntegerSerializer.INSTANCE.serializeLiteral(size, stream, offset);
    offset += OIntegerSerializer.INT_SIZE;

    if (context == null) {
      ChangeSerializationHelper.INSTANCE.serializeChanges(
          changes, OLinkSerializer.INSTANCE, stream, offset);
    } else {
      context.push(new ORidBagUpdateSerializationOperation(changes, collectionPointer));

      // 0-length serialized list of changes
      OIntegerSerializer.INSTANCE.serializeLiteral(0, stream, offset);
      offset += OIntegerSerializer.INT_SIZE;
    }

    return offset;
  }