socks-extensions.txt says username/password are ignored
In torspec's socks-extensions.txt, we say
and as of Tor 0.2.3.2-alpha, the "USERNAME/PASSWORD" (SOCKS5) authentication method  is supported too. Any credentials passed to the latter are ignored.
But don't we use them for stream isolation now?
Also (hit-and-run two-bugs-in-one-ticket faux pas, sorry), the Tor man page says:
IsolateSOCKSAuth Don’t share circuits with streams for which different SOCKS authentication was provided. (On by default; you can disable it with NoIsolateSOCKSAuth.)
which makes it sound like we look at SOCKS4 username too -- maybe we should change SOCKS to SOCKS5 in this man page stanza?