Fatal error: Uncaught Error: Class "Drupal\Core\Render\HtmlResponseAttachmentsProcessor" not found in /home/www/drupal8/test/core/modules/big_pipe/src/Render/BigPipeResponseAttachmentsProcessor.php:23 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/big_pipe/src/Render/BigPipeResponseAttachmentsProcessor.php on line 23