class RoundRobinLoadBalancer extends AbstractLoadBalancer {

    @Override
    public ProviderInfo doSelect(SofaRequest request, List<ProviderInfo> providerInfos) {
        String key = getServiceKey(request); // 每个方法级自己轮询，互不影响
        int length = providerInfos.size(); // 总个数
        PositiveAtomicCounter sequence = sequences.get(key);
        if (sequence == null) {
            sequences.putIfAbsent(key, new PositiveAtomicCounter());
            sequence = sequences.get(key);
        }
        return providerInfos.get(sequence.getAndIncrement() % length);
    }

    public  RoundRobinLoadBalancer(ConsumerBootstrap consumerBootstrap);

}