title: How to enable Hystrix circuit breaker at zuul?
body: <p>in my application we are using 
  springboot microservices , with eureka registry, zuul api gateway, 
  here assume I have 2 instances of payment-service, 
  and the zuul is using ribbon for loadbalancing the /payment endpoint to the payment-service, 
  when one node of the payment-service is unresponsive, and still registered with the  eureka. here we have configured the hystrix circuit breaker at Zuul apigateway, but hystrix circuit breaker is not getting opened for the unresponsive node. </p>