public function onAfterWrite()
 {
     try {
         if ($this->owner->isChanged('ID') || $this->owner->isChanged('Email') || $this->owner->isChanged('MemberID') || $this->owner->isChanged('FirstName') || $this->owner->isChanged('Surname')) {
             $data = CustomerDataExtractor::inst()->extract($this->owner);
             SS_Log::log("Adding/updating mailing list user: "******"Unable to add {$data['Email']} to mailing list: " . $e->getMessage(), SS_Log::WARN);
     }
 }
 /**
  * @param MailingListAdapter $adapter
  */
 public static function set_adapter(MailingListAdapter $adapter)
 {
     self::$adapter = $adapter;
 }