code: public boolean containsAll(final IntHashSet other) {
          final IntIterator iterator = other.iterator();
          while (iterator.hasNext()) {
              if (!contains(iterator.nextValue())) {
                  return false;
              }
          }
          return true;
      }
docs: IntHashSet specialised variant of {this#containsAll(Collection)}.
  
  @param other the int hashset to compare against.
  @return true if every element in other is in this.