"producer-max-rate" does work as expected in HornetQ with JAX-RS client

Issue

I am sending messages to a queue with this code:

 public static boolean sendMessageToQueue(final Serializable msg,
            final String queueName, final long expirationInMilliseconds) {

        InitialContext context = null;
        Connection connection = null;
        Destination destination = null;
        Session session = null;
        MessageProducer messageProducer = null;

        try {
            // create connection to JBoss server
            context = new InitialContext();
            // lookup for the clustered connection factory
            final ConnectionFactory connectionFactory =
                    (QueueConnectionFactory) context
                            .lookup(JAVA_CONNECTION_FACTORY);
            // initialize the send page messaging
            // lookup for the queue
            destination =
                    (Destination) context.lookup(QUEUE_PREFIX + queueName);
            // create connection
            connection = createJMSConnection(connectionFactory);
            // create session
            try {
                session =
                        connection.createSession(false,
                                Session.AUTO_ACKNOWLEDGE);
            } catch (final JMSException e) {
                closeResources(context, connection, session, messageProducer);
                connection = createJMSConnection(connectionFactory);
                session =
                        connection.createSession(false,
                                Session.AUTO_ACKNOWLEDGE);
            }
            // create producer to the queue
            messageProducer = session.createProducer(destination);
            // create the jms message

            final ObjectMessage message = session.createObjectMessage(msg);
            // final TextMessage message = session.createTextMessage(msg
            // .toString());

            if (expirationInMilliseconds > 0) {
                message.setJMSExpiration(expirationInMilliseconds);
            }

            messageProducer.send(message);
            return true;
        } catch (final JMSException ex) {
            ex.printStackTrace();
        } catch (final NamingException e) {
            e.printStackTrace();
        } finally {
            closeResources(context, connection, session, messageProducer);
        }
        return false;
    }

    private static Connection createJMSConnection(
            final ConnectionFactory connectionFactory) throws JMSException {

        // create connection
        final Connection connection = connectionFactory.createConnection();
        // start the queue connection
        connection.start();
        return connection;
    }

    private static void closeResources(final InitialContext context,
            final Connection connection, final Session session,
            final MessageProducer messageProducer) {

        try {
            if (context != null) {
                context.close();
            }
            if (session != null) {
                session.close();
            }
            if (messageProducer != null) {
                messageProducer.close();
            }
            if (connection != null) {
                connection.close();
            }
        } catch (final Exception e) {
        }
    }

• This is the method which uses this code:

        int count = Integer.valueOf(messages);
        for(int i=0;i<count;i++){
            String msg = "message number " + (i+1);
            JmsUtils.sendMessageToQueue(msg, "OrdersQueue");
            System.out.println("message: " + msg + " sent to OrdersQueue");
        }

• It works fine but if I add the "producer-max-rate" element to the pooled-connection-factory name="hornetq-ra" then I can see that the printing System.out.println("message: " + msg + " sent to OrdersQueue");
  is done only every second. Why is this behaviour?

                    <pooled-connection-factory name="hornetq-ra">
                       <producer-max-rate>50</producer-max-rate>
                        <transaction mode="xa"></transaction>
                        <connectors>
                            <connector-ref connector-name="in-vm"></connector>
                        </connectors>
                        <entries>
                            <entry name="java:/JmsXA"></entry>
                        </entries>
                    </pooled-connection-factory>

• It does not matter which number I set in "producer-max-rate".