int counter() {
            return counter;
        }
This {@link LoadBalancer} selects an element using random and {@link WeightedObject#weight()}.
If there are A(weight 10), B(weight 4) and C(weight 6) elements, the chances that
elements are selected are 10/20, 4/20 and 6/20, respectively. If A is selected 10 times and B and C are not
selected as much as their weight, then A is removed temporarily and the chances that B and C are selected are
4/10 and 6/10.
core/src/main/java/com/linecorp/armeria/common/loadbalancer/WeightedRandomLoadBalancer.java