code: public void closeIterator(Address origin, Object requestId) {
        Set<Object> ids = ownerRequests.get(origin);
        if (ids != null) {
           ids.remove(requestId);
        }
        closeIterator(requestId);
     }
docs: Invoked to have handler forget about given iterator they requested. This should be invoked when an
  {@link Iterator} has been found to have completed {@link Iterator#hasNext()} is false or if the caller
  wishes to stop a given iteration early. If an iterator is fully iterated upon (ie. {@link Iterator#hasNext()}
  returns false, that invocation will also close resources related to the iterator.
  @param requestId the id of the iterator