Showcase predicate filters with timestamp in status

[clux]

This was impossible before kube 0.81.

Having a random timestamp in a status field would cause the controller to spin constantly as it kept triggering itself.
Now with predicates from kube-rs/kube#911 it is possible to avoid this and have timestamps (say) in status objects.

Probably not going to merge this as these are unstable interfaces, just showcasing it here atm.

[azat]

Hi @clux. Any plans on making this API stable? (maybe I should write to the issue instead...)

[clux]

Hey, that would be a kube issue. I think this is probably close. But want to have a think w.r.t. more complicated filters, because while they are useful right now, there are some more complicated filters we could do that could follow the same pattern. I don't think that should need to change the existing predicates though.

I'll open an issue in kube over the weekend probably, otherwise feel free to raise it.

EDIT: thought about it, seems completely reasonable. PR in kube-rs/kube#1578

[clux]

Updated this PR against current. Predicates are stabilised in 0.96, but the for_streams interface for Controller is not, hopefully we can settle this down if we get good confidence in the shared streams edge cases.