public Set<Integer> nodesThatShouldBeDown(ClusterState state) {
        return calculate(state).nodesThatShouldBeDown();
    }
@Test
    void retired_node_is_counted_as_down() {
        GroupAvailabilityCalculator calc = calcForHierarchicCluster(
                DistributionBuilder.withGroups(3).eachWithNodeCount(2), 0.99);
        assertThat(calc.nodesThatShouldBeDown(clusterState(
                "distributor:6 storage:6 .1.s:r")), equalTo(indices(0)));
    }