@Test
    public void testHasNodeAvailableOrConnectionReady() {
        NetworkClient client = createNetworkClientWithMaxInFlightRequestsPerConnection(1, reconnectBackoffMaxMsTest);
        awaitReady(client, node);

        long now = time.milliseconds();
        LeastLoadedNode leastLoadedNode = client.leastLoadedNode(now);
        assertEquals(node, leastLoadedNode.node());
        assertTrue(leastLoadedNode.hasNodeAvailableOrConnectionReady());

        MetadataRequest.Builder builder = new MetadataRequest.Builder(Collections.emptyList(), true);
        ClientRequest request = client.newClientRequest(node.idString(), builder, now, true);
        client.send(request, now);
        client.poll(defaultRequestTimeoutMs, now);

        leastLoadedNode = client.leastLoadedNode(now);
        assertNull(leastLoadedNode.node());
        assertTrue(leastLoadedNode.hasNodeAvailableOrConnectionReady());
    }
This is a helper method that will execute two produce calls. The first call is expected to work and the
second produce call is intentionally made to emulate a request timeout. In the case that a timeout occurs
during a request, we want to ensure that we {@link Metadata#requestUpdate() request a metadata update} so that
on a subsequent invocation of {@link NetworkClient#poll(long, long) poll}, the metadata request will be sent.

<p/>

The {@link MetadataUpdater} has a specific method to handle
{@link NetworkClient.DefaultMetadataUpdater#handleServerDisconnect(long, String, Optional) server disconnects}
which is where we {@link Metadata#requestUpdate() request a metadata update}. This test helper method ensures
that is invoked by checking {@link Metadata#updateRequested()} after the simulated timeout.

@param requestTimeoutMs Timeout in ms
clients/src/test/java/org/apache/kafka/clients/NetworkClientTest.java