code: public SubscribersInfo getPushStatusForMessage(String messageId) throws IOException {
          String url = "queues/" + name + "/messages/" + messageId + "/subscribers";
          IronReader reader = client.get(url);
          SubscribersInfo subscribersInfo = gson.fromJson(reader.reader, SubscribersInfo.class);
          reader.close();
          return subscribersInfo;
      }
docs: Get push info of message by message id. If there is no message, an EmptyQueueException is thrown.
  @param messageId The Message ID.
  @throws io.iron.ironmq.HTTPException If the IronMQ service returns a status other than 200 OK.
  @throws java.io.IOException If there is an error accessing the IronMQ server.