@Override
          public int getCount() {
            Count count = mapEntry.getValue();
            if (count == null || count.get() == 0) {
              Count frequency = backingMap.get(getElement());
              if (frequency != null) {
                return frequency.get();
              }
            }
            return (count == null) ? 0 : count.get();
          }
        };
      }

    return oldCount;
  }

  @CanIgnoreReturnValue
  @Override
  public final int setCount(@ParametricNullness E element, int count) {
    checkNonnegative(count, "count");
    int oldCount = (count == 0) ? backingMap.remove(element) : backingMap.put(element, count);
    size += (count - oldCount);
    return oldCount;
  }

  @Override