private static Map<String, List<Endpoint>> selectEndpoints(int iteration, EndpointGroup xdsEndpointGroup) {
        final List<Endpoint> selectedEndpoints = new ArrayList<>();
        for (int i = 0; i < iteration; i++) {
            selectedEndpoints.add(xdsEndpointGroup.select(ctx(), CommonPools.workerGroup()).join());
            selectedEndpoints.add(xdsEndpointGroup.select(ctx(), CommonPools.workerGroup()).join());
        }
        return selectedEndpoints.stream().collect(Collectors.groupingBy(Endpoint::host));
    }
WeightedRandomLoadBalancer is random, so we just call selectNow
for a full iteration to consume all pending entries.
xds/src/test/java/com/linecorp/armeria/xds/client/endpoint/RampingUpTest.java