int entryCount = entry.getCount();
          return countMap.remove(element, entryCount);
        }
        return false;
      }

      /** The hash code is the same as countMap's, though the objects aren't equal. */
      @Override
      public int hashCode() {
        return countMap.hashCode();
      }
    }

    /** We use a special form of unboxing that treats null as zero. */