public void GetSecurity(SecurityInformation RequestedInformation,
                                out IntPtr ppSecurityDescriptor, [MarshalAs(UnmanagedType.Bool)] bool fDefault)
        {
            byte[] raw_sd = _sd ?? _handle.GetSecurityDescriptorBytes(RequestedInformation);
            IntPtr ret    = Win32NativeMethods.LocalAlloc(0, new IntPtr(raw_sd.Length));

            Marshal.Copy(raw_sd, 0, ret, raw_sd.Length);
            ppSecurityDescriptor = ret;
        }