feature: `net` connection timeouts should update when getting a message

[nick1udwig]

Currently, net connections timeout after some fixed period of time, e.g.:

https://github.com/kinode-dao/kinode/blob/main/kinode/src/net/tcp/utils.rs#L85

It would be better if they instead timed out after a period of time since last message.

We should also consider whether the current timeout of 30m is appropriate. Should it be shorter?

[dr-frmr]

Are you sure? My understanding of the select statement here is that the timeout is actually dropped if one of the other branches (send or receive) completes first

[dr-frmr]

Thinking closely about this actually makes me slightly concerned that sent/received messages could be dropped if they occur near-simultaneously here -- need to check.

[nick1udwig]

Sorry, missed the notif here.

Are you sure? My understanding of the select statement here is that the timeout is actually dropped if one of the other branches (send or receive) completes first

You're right, but because both read and write are infinite loops that only break on error, I think this leads to non-erroring connections having fixed lifetimes unrelated to their activity. This isn't terrible, but could be improved by keeping active connections alive.

[dr-frmr]

you're right -- i'll fix

[dr-frmr]

https://github.com/Enigma-Dark/kinode-engagement/issues/18#issuecomment-2481725115

funny enough--looks like we're better off forcing reconnections (after 30 minutes!) as a way to rotate session keys

[nick1udwig]

lol nice

If we ever want to run Kinode on a phone, we'll probably want to have much shorter-lived connections (to save on the "keep-alive" ping battery costs), but we can always revisit this if that becomes something we're actually considering implementing.