@Override
	public void onApplicationEvent(ApplicationEvent event) {
		executor.execute(() -> {
			Map<Tags, Long> aggregatedCounts = collectAggregatedCounts();
			registerMetrics(aggregatedCounts);
		});
	}
{@link SmartApplicationListener} for collecting event metrics from
{@link PeerAwareInstanceRegistry}.

@author Wonchul Heo
@author Olga Maciaszek-Sharma
@since 4.1.2
spring-cloud-netflix-eureka-server/src/main/java/org/springframework/cloud/netflix/eureka/server/metrics/EurekaInstanceMonitor.java