proxy_cache_bypass documentation?

[Dayo]

I moved my installation from the old stable 0.7.x branch to the new
stable 0.8.x and cannot proceed as I get an error message saying
proxy_cache_bypass must be used along with proxy_no_cache since v0.8.46.
However, it seems proxy_cache_bypass is not documented anywhere (can't
find it on the wiki anyway apart from one statement in the 0.8.46
changelog listing it as a new feature).

Can anyone kindly point me to where I can find documentation on this?

Thanks

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,135883,135883#msg-135883