About Sharing function in ZXing

I found this :

 Bitmap bitmap = QRCodeEncoder.encodeAsBitmap(contents, format, pixelResolution, pixelResolution);

      Message message = Message.obtain(handler, R.id.encode_succeeded);

      message.obj = bitmap;

      message.sendToTarget();

in the Intent.java class.

So, I somewhat understand that it sends to the "Handler" by "sendToTarget" method in handler class.  Then the 

http://code.google.com/p/zxing/source/browse/trunk/android/src/com/google/zxing/client/android/result/ResultHandler.java?r=1813

In that

  final void shareByEmail(String contents) {

    sendEmailFromUri("mailto:", null, activity.getString(R.string.msg_share_subject_line),

        contents);
  }