code: public static <E> int iterableSize(Iterable<E> itrbl) {
  	int size = 0;
  	for (Iterator<E> iter = itrbl.iterator(); iter.hasNext();) {
  		iter.next();
  		size++;
  	}
  	return size;
      }
docs: Computes, in linear time, the length of an
  <code>Iterable</code>.  This is done by iterating over all
  elements from <code>itrbl</code> and counting their number.