/**
  * Sends a service request.
  *
  * @param string $url The service url.
  *
  * @return \Widop\HttpAdapter\HttpResponse The response.
  *
  * @throws \Ivory\GoogleMap\Exception\ServiceException If the response is null.
  * @throws \Ivory\GoogleMap\Exception\ServiceException If the response has an error 4XX or 5XX.
  */
 protected function send($url)
 {
     $response = $this->httpAdapter->getContent($url);
     if ($response === null) {
         throw ServiceException::invalidServiceResult();
     }
     $statusCode = (string) $response->getStatusCode();
     if ($statusCode[0] === '4' || $statusCode[0] === '5') {
         throw ServiceException::invalidResponse($url, $statusCode);
     }
     return $response;
 }