Feature request: allow to access processed messages

[dreamorosi]

Use Case

In the Python version of Powertools for AWS customers using the Batch Processing utility are able to access an array of the processed batch to apply further processing. This is useful for those customers who might want to apply some special handling to successes/failures like creating custom metrics, or notifying an out-of-bounds downstream service.

Solution/User Experience

Refer to RFC #1082, section 4.2

Acceptance criteria

• The implementation allows the same degree of access/customization that the reference implementation has, while staying idiomatic with Node.js
• Return and input types of each method are appropriate
• Unit tests are implemented with 100% coverage
• Any new method is documented via docstrings, following project's conventions as much as possible

[dreamorosi]

With #1588 merged, the implementation introduced in the PR already allows you to access the processed messages.

This feature is used extensively in the unit tests to assert on the output of the process() method.

[erikayao93]

Implementation was finished as stated

[github-actions]

⚠️ COMMENT VISIBILITY WARNING ⚠️

Comments on closed issues are hard for our team to see.
If you need more assistance, please either tag a team member or open a new issue that references this one.
If you wish to keep having a conversation with other community members under this issue feel free to do so.