code: private boolean checkNeedCircuitBreak(Invoker<?> invoker, Invocation invocation) {
          String interfaceName = invoker.getUrl().getParameter(Constants.INTERFACE_KEY);
          String method = invocation.getMethodName();
          String methodKey = Config.getMethodPropertyName(invoker, invocation).toString();
          int limit = Config.getBreakLimit(invoker, invocation);
          BreakCounter breakCounter = breakCounterMap.get(methodKey);
          if(breakCounter!=null&&breakCounter.isEnable()){
              long currentExceptionCount = breakCounter.getCurrentExceptionCount();
              long currentBreakCount = breakCounter.getCurrentBreakCount();
              logger.info("[{}] check invoke [{}.{}] circuit break,current exception count [{}]  limit [{}]", localHost, interfaceName, method, currentExceptionCount, limit);
              if(limit<=currentExceptionCount){
                  if(currentBreakCount>0&&needRetry(invoker, invocation, currentBreakCount)){
                      logger.info("[{}] retry invoke [{}.{}] current break count [{}]",localHost,interfaceName,method,currentBreakCount);
                      breakCounter.incrementRetryTimes();
                      return false;
                  }
                  return true;
              }
          }
          return false;
      }
docs: 这里会判断当前调用服务的状态，分析判断是否需要进入降级状态
  如果服务在指定的时间区间内累积的错误，达到了配置的次数，则进入服务降级
  如果满足上面条件，并且满足重试机制，则也不会进入降级流程，而是触发远程服务调用
  @param invoker
  @param invocation
  @return