- Store message as UTF8 text, not blob
- `_push message` and the response on `send` should give the msgid, so the client can implement replies
- Message replies: referenced message should be msgid
- Somehow communicate (push? poll?) to room members whether a particular user is currently _active_, not just online.
- A session is marked inactive 2 minutes after the latest activity on that session. Make the number "2" configurable and not a hard-coded constant.
- Use poll(2), not select(2)
- Fix OOM dos vector
- Sub-linear hash table of conn_data's in main.c