@Override
    public void notify(ZuulFilter<?, ?> filter, ExecutionStatus status) {
        registry.counter(
                        "zuul.filter-" + filter.getClass().getSimpleName(),
                        "status",
                        status.name(),
                        "filtertype",
                        filter.filterType().toString())
                .increment();
    }
Publishes a counter metric for each filter on each use.
zuul-core/src/main/java/com/netflix/zuul/BasicFilterUsageNotifier.java