Return original attributes from webflux ClientRequest

[Dyuvarov]

Description

Spring request has attributes. The current implementation of ClientRequest from org.zalando.logbook.spring.webflux returns an empty attribute map whether there are attributes or not.
This improvement gives access to the spring request attributes from ClientRequest.getAttributes(). Also added AllAttributesExtractor class to extract all attributes from original request.

Motivation and Context

In a project my team is working on, we pass some data for spring WebClient request and response audit log messages via attributes. Now we have to use reflection to access them in the AttributeExtractor implementation because ClientRequest.getAttributes() returns HttpAttributes.EMPTY by default

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.

[Dyuvarov]

@whiskeysierra @lukasniemeier-zalando @kasmarian @msdousti
Hello, guys. This is just a friendly reminder to review this pull request. Thanks!

[msdousti]

Thanks for opening this PR. I like the idea of ClientRequest returning the request.attributes as provided by the Spring Framework.

Please take a look at my comments on AllAttributesExtractor.

[msdousti]

@Dyuvarov Thanks a lot for your contribution!

@kasmarian The PR is OK from my side :)

[kasmarian]

👍

[kasmarian]

Thank you for the PR and for the review 👏