Reduce subsystem channel size on test networks

[eskimor]

This way we can detect issues due to blocking channels on test networks better.

Given that the bounded channel size for subsystems seems to get passed into the overseer-gen macro a command line argument might be a bit too much to ask.

I'd suggest to use a feature flag that gets enabled on CI, but not for proper releases (we already had a similar setup in the past).

[drahnr]

if we want this for a one-off test, we could just use the annotation #[overlord(.., message_capacity=16, ..)] and that's it. If you'd want this to be dynamic, that's definitely do-able, just requires maybe one or two more additions to the builder pattern.

[eskimor]

Let's keep things simple. A feature flag that can be enabled on CI, but not for releases should already do the trick.

[drahnr]

My formulation might have been unclear, the above is already impl'd and works :)

[eskimor]

Wait, the feature flag itself does not exist yet - right? I will take care of that, but too soon to close then.

[drahnr]

That's correct, no cargo feature flag, but nothing todo and for a one-off, just creating a PR with the above changed setting might be enough.

[eskimor]

I would expect us to deploy this on a couple of nodes - fix any issues and then have it deployed by default on test nets, like Versi. Hence the feature flag.

[drahnr]

I'll create a lil smith tomorrow