code: public function post($url, $params)
      {
          if (is_array($params)) {
              $params = $this->filterParams($params);
          }
          $this->lastRequestParams = $params;
          $this->lastRequestUrl = $this->buildUrl($url);
          return $this->curlAgent->setOption(CURLOPT_POSTFIELDS, $params)
              ->post($this->lastRequestUrl, $this->rawResponse);
      }
docs: Performs POST HTTP request
  @author Adegoke Obasa <goke@cottacush.com>
  @param $url
  @param $params
  @return mixed