/** @throws Exception If failed. */
  public void testIoMetrics() throws Exception {
    Ignite ignite0 = grid();
    Ignite ignite1 = startGrid(1);

    Object msg = new TestMessage();

    int size = ignite0.configuration().getMarshaller().marshal(msg).length;

    assert size > MSG_SIZE;

    final CountDownLatch latch = new CountDownLatch(MSG_CNT);

    ignite0
        .message()
        .localListen(
            null,
            new MessagingListenActor<TestMessage>() {
              @Override
              protected void receive(UUID nodeId, TestMessage rcvMsg) throws Throwable {
                latch.countDown();
              }
            });

    ignite1
        .message()
        .localListen(
            null,
            new MessagingListenActor<TestMessage>() {
              @Override
              protected void receive(UUID nodeId, TestMessage rcvMsg) throws Throwable {
                respond(rcvMsg);
              }
            });

    for (int i = 0; i < MSG_CNT; i++) message(ignite0.cluster().forRemotes()).send(null, msg);

    latch.await();

    ClusterMetrics metrics = ignite0.cluster().localNode().metrics();

    info("Node 0 metrics: " + metrics);

    // Time sync messages are being sent.
    assert metrics.getSentMessagesCount() >= MSG_CNT;
    assert metrics.getSentBytesCount() > size * MSG_CNT;
    assert metrics.getReceivedMessagesCount() >= MSG_CNT;
    assert metrics.getReceivedBytesCount() > size * MSG_CNT;

    metrics = ignite1.cluster().localNode().metrics();

    info("Node 1 metrics: " + metrics);

    // Time sync messages are being sent.
    assert metrics.getSentMessagesCount() >= MSG_CNT;
    assert metrics.getSentBytesCount() > size * MSG_CNT;
    assert metrics.getReceivedMessagesCount() >= MSG_CNT;
    assert metrics.getReceivedBytesCount() > size * MSG_CNT;
  }