Neos\Flow\Http\Response::getStatusMessageByCode PHP Method

    public static function getStatusMessageByCode($statusCode)
    {
        $statusMessages = [100 => 'Continue', 101 => 'Switching Protocols', 102 => 'Processing', 200 => 'OK', 201 => 'Created', 202 => 'Accepted', 203 => 'Non-Authoritative Information', 204 => 'No Content', 205 => 'Reset Content', 206 => 'Partial Content', 207 => 'Multi-Status', 300 => 'Multiple Choices', 301 => 'Moved Permanently', 302 => 'Found', 303 => 'See Other', 304 => 'Not Modified', 305 => 'Use Proxy', 307 => 'Temporary Redirect', 400 => 'Bad Request', 401 => 'Unauthorized', 402 => 'Payment Required', 403 => 'Forbidden', 404 => 'Not Found', 405 => 'Method Not Allowed', 406 => 'Not Acceptable', 407 => 'Proxy Authentication Required', 408 => 'Request Timeout', 409 => 'Conflict', 410 => 'Gone', 411 => 'Length Required', 412 => 'Precondition Failed', 413 => 'Request Entity Too Large', 414 => 'Request-URI Too Long', 415 => 'Unsupported Media Type', 416 => 'Requested Range Not Satisfiable', 417 => 'Expectation Failed', 418 => 'Sono Vibiemme', 500 => 'Internal Server Error', 501 => 'Not Implemented', 502 => 'Bad Gateway', 503 => 'Service Unavailable', 504 => 'Gateway Timeout', 505 => 'HTTP Version Not Supported', 507 => 'Insufficient Storage', 509 => 'Bandwidth Limit Exceeded'];
        return isset($statusMessages[$statusCode]) ? $statusMessages[$statusCode] : 'Unknown Status';
    }

 /**
  * @return integer
  */
 public function getStatusCode()
 {
     $statusCode = $this->tsValue('statusCode');
     if ($statusCode === null) {
         $statusCode = 200;
     }
     if (Response::getStatusMessageByCode($statusCode) === 'Unknown Status') {
         throw new \InvalidArgumentException('Unknown HTTP status code', 1412085703);
     }
     return (int) $statusCode;
 }