isCleanUrl example

$path = \Drupal::config('system.file')->get('default_scheme') . '://' . $path;
      }
      $original_uri = $stream_wrapper_manager->normalizeUri($path);
      $token_query = [IMAGE_DERIVATIVE_TOKEN => $this->getPathToken($original_uri)];
    }

    if ($clean_urls === NULL) {
      // Assume clean URLs unless the request tells us otherwise.       $clean_urls = TRUE;
      try {
        $request = \Drupal::request();
        $clean_urls = RequestHelper::isCleanUrl($request);
      }
      catch (ServiceNotFoundException $e) {
      }
    }

    // If not using clean URLs, the image derivative callback is only available     // with the script path. If the file does not exist, use Url::fromUri() to     // ensure that it is included. Once the file exists it's fine to fall back     // to the actual file path, this avoids bootstrapping PHP once the files are     // built.     if ($clean_urls === FALSE && $stream_wrapper_manager::getScheme($uri) == 'public' && !file_exists($uri)) {