Scalr\Service\Aws\Client\QueryClient::tryCall PHP Method

    protected function tryCall($httpRequest, $attempts = 3, $interval = 200)
    {
        try {
            $httpResponse = \Scalr::getContainer()->http->sendRequest($httpRequest);
            if (preg_match('/^<html.+ Service Unavailable/', $httpResponse->getBody()->toString()) && --$attempts > 0) {
                usleep($interval);
                return $this->tryCall($httpRequest, $attempts, $interval * 2);
            }
            //Increments the queries quantity
            $this->_incrementQueriesQuantity();
            $response = new QueryClientResponse($httpResponse);
            $response->setRequest($httpRequest);
            $response->setQueryNumber($this->getQueriesQuantity());
            if ($response->hasError()) {
                $eventObserver = $this->getAws()->getEventObserver();
                /* @var $clientException ClientException */
                $clientException = $response->getException();
                //It does not need anymore
                //$response->setEventObserver($eventObserver);
                if (isset($eventObserver) && $eventObserver->isSubscribed(EventType::EVENT_ERROR_RESPONSE)) {
                    $eventObserver->fireEvent(new ErrorResponseEvent(array('exception' => $clientException, 'apicall' => $clientException->getApiCall())));
                }
                if ($clientException->getErrorData() instanceof ErrorData && $clientException->getErrorData()->getCode() == ErrorData::ERR_REQUEST_LIMIT_EXCEEDED) {
                    if (--$attempts > 0) {
                        //Tries to handle RequestLimitExceeded AWS Response
                        $sleepTimeout = 3 * (3 - $attempts);
                        sleep($sleepTimeout > 0 ? $sleepTimeout : 3);
                        return $this->tryCall($httpRequest, $attempts, $interval);
                    }
                }
            }
            if (is_callable($this->callback)) {
                call_user_func($this->callback, $httpRequest, $httpResponse);
            }
        } catch (\http\Exception $e) {
            $error = new ErrorData();
            $error->message = 'Cannot establish connection to AWS server. ' . (isset($e->innerException) ? preg_replace('/(\\(.*\\))/', '', $e->innerException->getMessage()) : $e->getMessage());
            throw new ClientException($error);
        }
        return $response;
    }