code: public static void sendMessageInBackground(String message,
                                               AVQuery<? extends AVInstallation> query, final SendCallback callback) {
      AVPush push = new AVPush();
      push.setMessage(message);
      push.setQuery(query);
      push.sendInBackground(callback);
    }
docs: A helper method to concisely send a push message to a query. This method is equivalent to
  
  <pre>
  AVPush push = new AVPush();
  push.setMessage(message);
  push.setQuery(query);
  push.sendInBackground(callback);
  </pre>
  
  @param message The message that will be shown in the notification.
  @param query A AVInstallation query which specifies the recipients of a push.
  @param callback callback.done(e) is called when the send completes.