impl Map::retain and Set::retain

[pitaj]

also test examples and benches in CI

relates #11

[udoprog]

Retain impl LGTM, I'd like the examples to be cleaner though. Easiest would be to only build examples with the full set of features (and no need to #[test] them).

[pitaj]

Understood on the examples, but can you restore the one you deleted (map_feature) and just remove the feature stuff? It is really helpful for debugging derive with composite keys.

[udoprog]

Understood on the examples, but can you restore the one you deleted (map_feature) and just remove the feature stuff? It is really helpful for debugging derive with composite keys.

Ah. Not sure I want to have a permanent example for this since they're meant to be demonstrative uses of the library. 🤔 What if we keep it as a test? Then you can run it with cargo build --test <name>?

[udoprog]

The empty example should probably also be moved*!

[udoprog]

All right, with this you can now check all expansions with:

cargo install cargo-expand # if you don't already have it
cargo expand --test map_feature

Be warned: it's VERY noisy. :)

Does that work for you?

[pitaj]

That works, thanks