code: public function generateText()
      {
          $result = 'SPD' . self::DELIMITER . $this->version . self::DELIMITER . $this->implodeContent();
  
          if ($this->appendCRC32) {
              $result .= self::DELIMITER . 'CRC32:' . sprintf('%x', crc32($result));
          }
  
          return $result;
      }
docs: Generate SPD as text
  
  @return string