docs: @Nonnegative
    public long getSize ()
    {
      if (m_nSize >= 0)
        return m_nSize;
      if (m_aCachedContent != null)
        return m_aCachedContent.length;
      if (m_aDFOS.isInMemory ())
        return m_aDFOS.getDataLength ();
      return m_aDFOS.getFile ().length ();
    }