@Override
                public void run() {
                    int corePoolSize = getCorePoolSize();
                    defaultServerListUpdateExecutor.setCorePoolSize(corePoolSize);
                    defaultServerListUpdateExecutor.setMaximumPoolSize(corePoolSize * 5);
                }
A server list updater for the {@link com.netflix.loadbalancer.DynamicServerListLoadBalancer} that
utilizes eureka's event listener to trigger LB cache updates.

Note that when a cache refreshed notification is received, the actual update on the serverList is
done on a separate scheduler as the notification is delivered on an eurekaClient thread.

@author David Liu
ribbon-eureka/src/main/java/com/netflix/niws/loadbalancer/EurekaNotificationServerListUpdater.java