Map<Node, List<MetricsPacket>> getMetrics() {
        return getMetrics(defaultMetricsConsumerId);
    }
@Test
    public void dead_node_yields_empty_metrics() {
        var config = nodesConfig("/non-existent");
        Node node = new Node(config.node(0));

        ApplicationMetricsRetriever retriever = new ApplicationMetricsRetriever(config);
        var metricsByNode = retriever.getMetrics();
        assertEquals(1, metricsByNode.size());
        assertEquals(0, metricsByNode.get(node).size());

    }