code: public CircuitBreaker build() {
          if (counterSlidingWindow.compareTo(counterUpdateInterval) <= 0) {
              throw new IllegalStateException(
                      "counterSlidingWindow: " + counterSlidingWindow + " (expected: > counterUpdateInterval)");
          }
          return new NonBlockingCircuitBreaker(
                  ticker,
                  new CircuitBreakerConfig(name, failureRateThreshold, minimumRequestThreshold,
                                           circuitOpenWindow, trialRequestInterval,
                                           counterSlidingWindow, counterUpdateInterval,
                                           Collections.unmodifiableList(listeners)));
      }
docs: Returns a newly-created {@link CircuitBreaker} based on the properties of this builder.