docs: public static IntSet from(PrimitiveIterator.OfInt iterator) {
        boolean hasNext = iterator.hasNext();
        if (!hasNext) {
           return EmptyIntSet.getInstance();
        }
        int firstValue = iterator.nextInt();
        hasNext = iterator.hasNext();
        if (!hasNext) {
           return new SingletonIntSet(firstValue);
        }
        // We have 2 or more values so just set them in the SmallIntSet
        SmallIntSet set = new SmallIntSet();
        set.set(firstValue);
        iterator.forEachRemaining((IntConsumer) set::set);
        return set;
     }