[boost] [range] RFC: span(iterator, size)

Hi there, I want to query if there's any interest in such a utility: span(iterator, size) : iterator_range which simply returns iterator_range(it, it + size) for RandomAccessIterator; for others modeling ForwardIterator, a special iterator adaptor, say, counted_iterator is used, so we don't have to advance it just for getting the end iterator. Thoughts?