function passthrough( $startOffset = 0, $length = false )
    {
        eZDebugSetting::writeDebug( 'kernel-clustering', "dfs::passthrough( '{$this->filePath}', $startOffset, $length )" );
        self::$dbbackend->_passThrough( $this->filePath, $startOffset, $length, "dfs::passthrough( '{$this->filePath}'" );
    }