@Override
  protected int nextRecordId() {
    if (headerPage == null) {
      throw new AlreadyDisposedException("Storage is closed");
    }
    ByteBuffer headerBuffer = headerPage.rawPageBuffer();
    return (int)INT_HANDLE.getVolatile(headerBuffer, HeaderLayout.NEXT_RECORD_ID_OFFSET);
  }
@Override
  protected int nextRecordId()