Add feature for limit request to log in middleware logger using status code

[tglman]

Hi,
This is yet a preliminary change to just collect feedback:

So this PR add a new feature on the logger middleware, to limit the logging to a range of status code, so that are logged only some specific status in the range, a simple example that will log only the 400+ request/responses is:

        Logger::default().statuses(StatusCode::BAD_REQUEST..);

Do you like this API is the naming right or you prefer a different one ?
Do you like this? shall I continue 😄 ?

PR Checklist

• Tests for the changes have been added / updated.
  Could not really find a simple way to test this without an application, I didn't see any similar tests for other similar features where could I find/plug a test case for this case ?
• Documentation comments have been added / updated.
  work in progress
• A changelog entry has been made for the appropriate packages.
  will do
• Format code with the latest stable rustfmt.
• (Team) Label with affected crates and semver status.

[tglman]

Hi,

I did add a simple dev-dependency to capture logs and check them in the tests, so I could add some tests that check the full flow, I updated also some existing tests to check that the output is what is expected.

Now this PR should be complete of all the requirements.

Regards

[robjtede]

The only problem I see with this is the issue of disjoint ranges. I can see it being reasonable to want everything except redirects being logged; in which case it's either:

• 100..=299 ∪ 400..=999
• 100..=999 ∖ 300..=399

It's tempting to go with the set subtraction technique since more common patterns can be expressed with just one builder method. Despite being terse, it might be confusing, too.

So, the API could be log_enabled: Vec<Range<StatusCode>>.