@Override
  boolean mayHaveChildren(final int fileId) throws IOException {
    PersistentFSConnection.ensureIdIsValid(fileId);
    if (fileId == SUPER_ROOT_ID) {
      throw new AssertionError(
        "Incorrect call .mayHaveChildren() with is a super-root record id(=" + SUPER_ROOT_ID + ")" +
        "Super-root is a special file record for internal use, it MUST NOT be used directly"
      );
    }

    final Boolean hasChildren = attributeAccessor.readAttributeRaw(fileId, CHILDREN_ATTR, buffer -> {
      final int count = DataInputOutputUtil.readINT(buffer);
      return Boolean.valueOf(count != 0);
    });
    if (hasChildren == null) {
      return true; //we don't know about children => maybe have, maybe not...
    }
    return hasChildren.booleanValue();
  }
@Override
  boolean mayHaveChildren(final int fileId)