/**
  *  send gmail
  *
  *  TODO: 請加入附件, 但應該不是在這個 method 擴充
  *
  *  @return boolean
  */
 public static function sendMessage($from, $to, $subject, $body)
 {
     $mail = new \Nette\Mail\Message();
     $mail->setFrom($from)->addTo($to)->setSubject($subject)->setBody($body);
     $messageText = $mail->generateMessage();
     $data = self::_encodeRawData($messageText);
     try {
         $message = new Google_Service_Gmail_Message();
         $message->setRaw($data);
         self::getService()->users_messages->send("me", $message);
     } catch (Exception $e) {
         echo 'Send message error ' . $e->getMessage() . "\n";
         return false;
     }
     return true;
 }