code: @Override
      public int compareTo(Request<T> other) {
          Priority left = this.getPriority();
          Priority right = other.getPriority();
  
          // High-priority requests are "lesser" so they are sorted to the front.
          // Equal priorities are sorted by sequence number to provide FIFO ordering.
          return left == right ?
                  this.sequence - other.sequence :
                  right.ordinal() - left.ordinal();
      }
docs: Our comparator sorts from high to low priority, and secondarily by
  sequence number to provide FIFO ordering.