@Override
    public String toString(){
        StringBuilder sb = new StringBuilder("ZoneAffinityServerListFilter:");
        sb.append(", zone: ").append(zone).append(", zoneAffinity:").append(zoneAffinity);
        sb.append(", zoneExclusivity:").append(zoneExclusive);
        return sb.toString();       
    }
@deprecated Must pass in a config via {@link ZoneAffinityServerListFilter#ZoneAffinityServerListFilter(IClientConfig)}
ribbon-loadbalancer/src/main/java/com/netflix/loadbalancer/ZoneAffinityServerListFilter.java