public function reset() {
        if (!is_resource($this->connection))
            throw new RuntimeException('Cannot reset connection: Not connected');

        $this->writeData('RSET');
        $response = $this->readResponse();

        $this->parseResponse($response);
        if ($this->responseStatus != 250)
            throw new RuntimeException('RSET command not accepted: '.$this->responseStatus.' '.$this->response.NL.NL.'SMTP transfer log:'.NL.'------------------'.NL.$this->logBuffer);
    }