private static SafeKernelObjectHandle OpenClipboardToken(TokenAccessRights desired_access)
        {
            SafeKernelObjectHandle handle;

            if (!Win32NativeMethods.GetClipboardAccessToken(out handle, desired_access
                                                            ))
            {
                throw new NtException(NtStatus.STATUS_NO_TOKEN);
            }
            return(handle);
        }