Zend_Http_Client::resetParameters PHP Method

    public function resetParameters($clearAll = false)
    {
        // Reset parameter data
        $this->paramsGet = array();
        $this->paramsPost = array();
        $this->files = array();
        $this->raw_post_data = null;
        $this->enctype = null;
        if ($clearAll) {
            $this->headers = array();
            $this->last_request = null;
            $this->last_response = null;
        } else {
            // Clear outdated headers
            if (isset($this->headers[strtolower(self::CONTENT_TYPE)])) {
                unset($this->headers[strtolower(self::CONTENT_TYPE)]);
            }
            if (isset($this->headers[strtolower(self::CONTENT_LENGTH)])) {
                unset($this->headers[strtolower(self::CONTENT_LENGTH)]);
            }
        }
        return $this;
    }

 /**
  * HTTP client preparation procedures - should be called before every API 
  * call. 
  * 
  * Will clean up the HTTP client parameters, set the request method to POST
  * and add the always-required authentication information
  * 
  * @param  string $method The API method we are about to use
  * @return void
  */
 protected function prepare($method)
 {
     // Reset parameters
     $this->httpClient->resetParameters();
     // Add authentication data
     $this->httpClient->setMethod('POST');
     $this->httpClient->setParameterPost(array('USER' => $this->authInfo->getUser(), 'PWD' => $this->authInfo->getPassword(), 'SIGNATURE' => $this->authInfo->getSignature(), 'VERSION' => '2.3', 'METHOD' => $method));
 }