//Issue.php
    /**
     * Create a new issue given an array of $params
     * The issue is assigned to the authenticated user.
     * @link http://www.redmine.org/projects/redmine/wiki/Rest_Issues#Creating-an-issue
     *
     * @param  array             $params the new issue data
     * @return \SimpleXMLElement
     */
    public function create(array $params = array())
    {
        $defaults = array(
            'subject'          => null,
            'description'      => null,

            // 'project'          => null,
            // 'category'         => null,
            // 'status'           => null,
            // 'tracker'          => null,
            // 'assigned_to'      => null,
            // 'author'           => null,

            'project_id'       => null,
            'category_id'      => null,
            'priority_id'      => null,
            'status_id'        => null,
            'tracker_id'       => null,
            'assigned_to_id'   => null,
            'author_id'        => null,
            'due_date'         => null,
            'start_date'       => null,
            'watcher_user_ids' => null,
        );
        $params = $this->cleanParams($params);
        $params = array_filter(array_merge($defaults, $params));

        $xml = $this->buildXML($params);

        return $this->post('/issues.xml', $xml->asXML());
        // $json = json_encode(array('issue' => $params));
        // return $this->post('/issues.json', $json);
    }


    //AbstractApi.php
    /**
     * {@inheritDoc}
     */
    public function post($path, $data)
    {
        return $this->client->post($path, $data);
    }


    //Client.php
    /**
     * HTTP POSTs $params to $path
     * @param  string $path
     * @param  string $data
     * @return mixed
     */
    public function post($path, $data)
    {
        return $this->runRequest($path, 'POST', $data);
    }

    /**
     * @param  string                        $path
     * @param  string                        $method
     * @param  string                        $data
     * @return false|SimpleXMLElement|string
     * @throws \Exception                    If anything goes wrong on curl request
     */
    private function runRequest($path, $method = 'GET', $data = '')
    {
        $this->responseCode = null;
        $this->getPort($this->url.$path);

        $curl = curl_init();
        if (isset($this->apikeyOrUsername) && $this->useHttpAuth) {
            if (null === $this->pass) {
                curl_setopt($curl, CURLOPT_USERPWD, $this->apikeyOrUsername.':'.rand(100000, 199999) );
            } else {
                curl_setopt($curl, CURLOPT_USERPWD, $this->apikeyOrUsername.':'.$this->pass );
            }
            curl_setopt($curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
        }
        curl_setopt($curl, CURLOPT_URL, $this->url.$path);
        curl_setopt($curl, CURLOPT_VERBOSE, 0);
        curl_setopt($curl, CURLOPT_HEADER, 0);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($curl, CURLOPT_PORT , $this->port);
        if (80 !== $this->port) {
            curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, $this->checkSslCertificate);
            curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, $this->checkSslHost);
        }

        $tmp = parse_url($this->url.$path);
        $httpHeader = array();
        if ('xml' === substr($tmp['path'], -3)) {
            $httpHeader[] = 'Content-Type: text/xml';
        }
        if ('/uploads.json' === $path || '/uploads.xml' === $path) {
            $httpHeader[] = 'Content-Type: application/octet-stream';
        } elseif ('json' === substr($tmp['path'], -4)) {
            $httpHeader[] = 'Content-Type: application/json';
        }

        if (!empty($httpHeader)) {
            if (null === $this->pass) {
                $httpHeader[] = 'X-Redmine-API-Key: '.$this->apikeyOrUsername;
            }
            curl_setopt($curl, CURLOPT_HTTPHEADER, $httpHeader);
        }

        switch ($method) {
            case 'POST':
                curl_setopt($curl, CURLOPT_POST, 1);
                if (isset($data)) {curl_setopt($curl, CURLOPT_POSTFIELDS, $data);}
                break;
            case 'PUT':
                curl_setopt($curl, CURLOPT_CUSTOMREQUEST, 'PUT');
                if (isset($data)) {curl_setopt($curl, CURLOPT_POSTFIELDS, $data);}
                break;
            case 'DELETE':
                curl_setopt($curl, CURLOPT_CUSTOMREQUEST, 'DELETE');
                break;
            default: // GET
                break;
        }
        $response = curl_exec($curl);
        $this->responseCode = curl_getinfo($curl, CURLINFO_HTTP_CODE);

        if (curl_errno($curl)) {
            $e = new \Exception(curl_error($curl), curl_errno($curl));
            curl_close($curl);
            throw $e;
        }
        curl_close($curl);

        if ($response) {
            // if response is XML, return an SimpleXMLElement object
            if ('<' === substr($response, 0, 1)) {
                return new \SimpleXMLElement($response);
            }

            return $response;
        }

        return true;
    }