You can do it simply by polling the channel every few w/e period is appropriate to you (1 min is okish) noting when the stream starts (results will say if its live).
Then take a poll of the users in stream (and you can repeat it to build a unique list of users during the stream) and turn off that user polling when you receive a “stream ended” event.
Yes, it sucks to poll every min or so, but…
there is a good blurb here:
cheers.