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"
      );
    }

    try (final DataInputStream input = attributeAccessor.readAttribute(fileId, CHILDREN_ATTR)) {
      if (input == null) return true;
      final int count = DataInputOutputUtil.readINT(input);
      return count != 0;
    }
  }
boolean mayHaveChildren(final int fileId)