[NNTP] Extension docs snapshots

[Russ Allbery]

Ken Murchison <ken at oceana.com> writes:

> As an aside, I notice that LIST EXTENSIONS is allowed to be pipelined
> (its not prohibited in -25).  Shouldn't we encourage friendly behavior
> and not allow it to be pipelined (at least not with optional
> commands/extensions)?  Either way, MODE STREAM should probably be
> consistent with LIST EXTENSIONS since its essentially a capability
> discovery command.

There's no problem with pipelining LIST EXTENSIONS and some other,
non-extension commands.  For example, a client on initial connection may
want to send LIST EXTENSIONS followed immediately by a sequence of GROUP
commands to get the count of unread articles in a set of groups.  There's
no reason to deny that.

That would also be fine with MODE STREAM, but the difference with MODE
STREAM is that a client that sends it is likely to send nothing other than
CHECK, TAKETHIS, and QUIT commands for the whole rest of the session, and
none of those make sense to pipeline with MODE STREAM.

-- 
Russ Allbery (rra at stanford.edu)             <http://www.eyrie.org/~eagle/>