private function makeRequest($method, $path, $headers = array(), $params = '') {
        if (time() - $this->previousRequestTime < 1) {
            sleep(1);
        }        
        $response = call_user_func_array(array($this->http, $method), array($path, $headers, $params));
        $this->previousRequestTime = time();
        list($status, $headers, $body) = $response;
        return $this->processResponse($response);
    }