The RTorrent query class can be used to send multiple queries over one XMLRPC command, thus heavily decreasing loading times.
It is created in RTorrent.query() or can be manually created using the RTorrentQuery() constructor.
It extends the MultiBase class, which is used in all the *Query classes. Head over to MultiBase to find more about the general *Query classes.
# Create a RTorrent class (or use an existing one)
r = RTorrent(host, port, url)
# Create the query.
rq = r.query().get_upload_rate().get_download_rate().get_librtorrent_version()
res = rq.first()
print res.get_upload_rate # Note that this is an attribute.