code: protected function boot()
      {
          if (defined('PHP_EOL')) {
              self::$LINE_ENDING = PHP_EOL;
          } else {
              self::$LINE_ENDING = (strpos(PHP_OS, 'WIN') === false) ? "\n" : "\r\n";
          }
          $this->setRegistry('X-Mailer', "PHP ".PHP_VERSION." - ".self::MM_CLASSNAME." ".self::MM_CLASSVERSION, 'headers');
      }
docs: First initialization of the object
  
  @return void