There are many code paths that invoke

   StatusWith<HostAndPort> getHostOrRefresh(const ReadPreferenceSetting& readPref,
                                             Milliseconds maxWait = kDefaultFindHostTimeout);

here. The default value is 15 seconds.

The timeout is not passed down to `refresher.refreshUntilMatches(criteria)` 20 lines lower. Essentially it is coded to spin forever here.