'Manually, synchronously fetch the next page. Supplied for manually retrieving pages
and inspecting :meth:`~.current_page`. It is not necessary to call this when iterating
through results; paging happens implicitly in iteration.'

def fetch_next_page(self):

    if self.response_future.has_more_pages:
        self.response_future.start_fetching_next_page()
        result = self.response_future.result()
        self._current_rows = result._current_rows
    else:
        self._current_rows = []
