private function send_request() {
        // check if stream is declared to be open
        // only logical check we are not sure if socket is really still open ...
        if ($this->_connection_closed) {
            // reopen it
            // be sure to close the open socket.
            $this->close();
            $this->reopen();
        }

        // convert array to string
        $buffer = implode("\r\n", $this->_req);
        $buffer .= "\r\n\r\n";
        $this->_error_log($buffer);
        fputs($this->sock, $buffer);
    }