@Override
    public boolean registerMetrics(MeterRegistry registry, MeterIdPrefix idPrefix) {
        final int numDelegates = delegates.size();
        switch (numDelegates) {
            case 0:
                return false;
            case 1:
                return delegates.get(0).registerMetrics(registry, idPrefix);
            default:
                boolean registered = false;
                for (int i = 0; i < numDelegates; i++) {
                    final MeterIdPrefix delegateIdPrefix = idPrefix.withTags("index", String.valueOf(i));
                    if (delegates.get(i).registerMetrics(registry, delegateIdPrefix)) {
                        registered = true;
                    }
                }
                return registered;
        }
    }
A {@link Router} implementation that enables composing multiple {@link Router}s into one.
core/src/main/java/com/linecorp/armeria/server/CompositeRouter.java