How to know Gcm Message is Recieved By recipient?

i am New in android ,and i am work with Gcm in android .i want get the status of message .it is Diliverd or not.my code below.sorry for poor English

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 private void sendMessage(List<SearchChildrenInformationData> searchedChildrensList) {
        {
            try {
                Sender sender = new Sender(GOOGLE_SERVER_KEY);
                Message message = new Message.Builder().timeToLive(50)
                        .delayWhileIdle(false).addData(MESSAGE_KEY, senderMessage)
                        .build();

                for (int i = 0; i <= searchedChildrensList.size() - 1; i++) {
                    String regid = searchedChildrensList.get(i).getSchoolId();
                    Result multiResult = sender
                            .send(message, regid, 1);
                    System.out.println("#####REsult++++" + multiResult);

                }
                searchedChildrensList.clear();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

`