private boolean shouldEnableZoneAffinity(List<T> filtered) {    
        if (!zoneAffinity && !zoneExclusive) {
            return false;
        }
        if (zoneExclusive) {
            return true;
        }
        LoadBalancerStats stats = getLoadBalancerStats();
        if (stats == null) {
            return zoneAffinity;
        } else {
            logger.debug("Determining if zone affinity should be enabled with given server list: {}", filtered);
            ZoneSnapshot snapshot = stats.getZoneSnapshot(filtered);
            double loadPerServer = snapshot.getLoadPerServer();
            int instanceCount = snapshot.getInstanceCount();            
            int circuitBreakerTrippedCount = snapshot.getCircuitTrippedCount();
            if (((double) circuitBreakerTrippedCount) / instanceCount >= blackOutServerPercentageThreshold.getOrDefault()
                    || loadPerServer >= activeReqeustsPerServerThreshold.getOrDefault()
                    || (instanceCount - circuitBreakerTrippedCount) < availableServersThreshold.getOrDefault()) {
                logger.debug("zoneAffinity is overriden. blackOutServerPercentage: {}, activeReqeustsPerServer: {}, availableServers: {}", 
                        new Object[] {(double) circuitBreakerTrippedCount / instanceCount,  loadPerServer, instanceCount - circuitBreakerTrippedCount});
                return false;
            } else {
                return true;
            }
            
        }
    }
@deprecated Must pass in a config via {@link ZoneAffinityServerListFilter#ZoneAffinityServerListFilter(IClientConfig)}
ribbon-loadbalancer/src/main/java/com/netflix/loadbalancer/ZoneAffinityServerListFilter.java