/** * @param object $command * @param Exception $exception * @return string|null */ public function commandFailed($command, Exception $exception) { $exceptionClass = get_class($exception); $exceptionMessage = $exception->getMessage(); return 'Command failed: ' . get_class($command) . ' ' . $this->serializer->encode($command) . " threw the exception {$exceptionClass} ({$exceptionMessage})"; }