Psr7Middlewares\Utils\Helpers::getOutput PHP Метод

    public static function getOutput($level)
    {
        $output = '';
        while (ob_get_level() >= $level) {
            $output .= ob_get_clean();
        }
        return $output;
    }

 /**
  * Execute the middleware.
  *
  * @param ServerRequestInterface $request
  * @param ResponseInterface      $response
  * @param callable               $next
  *
  * @return ResponseInterface
  */
 public function __invoke(ServerRequestInterface $request, ResponseInterface $response, callable $next)
 {
     ob_start();
     $level = ob_get_level();
     $method = Run::EXCEPTION_HANDLER;
     $whoops = $this->getWhoopsInstance($request);
     $whoops->allowQuit(false);
     $whoops->writeToOutput(false);
     $whoops->sendHttpCode(false);
     //Catch errors means register whoops globally
     if ($this->catchErrors) {
         $whoops->register();
     }
     try {
         $response = $next($request, $response);
     } catch (\Throwable $exception) {
         $body = self::createStream($response->getBody());
         $body->write($whoops->{$method}($exception));
         $response = $response->withStatus(500)->withBody($body);
     } catch (\Exception $exception) {
         $body = self::createStream($response->getBody());
         $body->write($whoops->{$method}($exception));
         $response = $response->withStatus(500)->withBody($body);
     } finally {
         Utils\Helpers::getOutput($level);
     }
     if ($this->catchErrors) {
         $whoops->unregister();
     }
     return $response;
 }