public Builder<T> withLoadBalancerContext(LoadBalancerContext loadBalancerContext) {
            this.loadBalancerContext = loadBalancerContext;
            return this;
        }
Pass in an optional key object to help the load balancer to choose a specific server among its
server list, depending on the load balancer implementation.
ribbon-loadbalancer/src/main/java/com/netflix/loadbalancer/reactive/LoadBalancerCommand.java