msgid Support

[andymandias]

Support for message-ids.

First step in restructuring PR #370.

[tarkah]

Simple enough!

We need to eventually handle outbound messages more gracefully, especially for servers that have echo-message so when supported we can:

• Show messages as failed to send if they aren't echo'd within a timeout
• Update our stored outbound message w/ the server chosen message id

We can use labeled-response as a way to match echo'd messages back to the original message we sent -> update it w/ server message id. If server doesn't support labeled-response but does support echo-message, we can use some timestamp / content comparison method I guess.

[andymandias]

Agreed re: outbound messages! The chathistory PR has changes to history that make the updating messages with their id clean & simple, so my inclination would be to wait for the history changes before implementing an id update for stored outbound messages. Detecting messages that fail to send, however, is not addressed at all by the chathistory PR.

[4e554c4c]

We can use labeled-response as a way to match echo'd messages back to the original message we sent -> update it w/ server message id. If server doesn't support labeled-response but does support echo-message, we can use some timestamp / content comparison method I guess.

keeping track of messages with echo-message but not labeled-response is a bit tricky. a good reference IMO is how goguma does it: https://codeberg.org/emersion/goguma/src/commit/d26acea8416739cc962a3b3f05c4c7b148f4bb5d/lib/client.dart#L786
That is, keep track of how many messages are sent vs received. If both are the same then you're generally in sync.

If neither are available it does a PING/PONG after each message to make sure that the connection is still stable.