code: public static RateLimiter createBurstingLimiter(final double rate, final double burstBucketSizeInSeconds) {
          final RateLimiter rateLimiter = new SmoothRateLimiter.SmoothBursty(RateLimiter.SleepingStopwatch.createFromSystemTimer(),
                  burstBucketSizeInSeconds /* maxBurstSeconds */);
          rateLimiter.setRate(rate);
          return rateLimiter;
      }
docs: https://github.com/google/guava/blob/v18.0/guava/src/com/google/common/util/concurrent/RateLimiter.java#L137