code: public int getCarrierPort(String bucketName) {
          Bucket bucket = buckets.get(bucketName);
          if (null == bucket) {
              // Buckets are created when the mock is started. Calling getCarrierPort()
              // before the mock has been started makes no sense.
              throw new RuntimeException("Bucket does not exist. Has the mock been started?");
          }
          return bucket.getCarrierPort();
      }
docs: Get the carrier port for a bucket.
  @param bucketName The bucket name to fetch the carrier port for.
  @return The carrier port.