code: @Override
      public int compareTo(ConcurrentServiceReferenceElement<T> that) {
          // Note: that.compareTo(this) will sort highest ranking first.
          int compare = that.serviceRanking.compareTo(this.serviceRanking);
          if (compare == 0) {
              compare = this.serviceId.compareTo(that.serviceId);
          }
  
          return compare;
      }
docs: {@inheritDoc}