Possible meta around performance testing of function calls

Problem/Motivation

From @catch over at 🐛 Improve the performance of \Drupal\Core\Update\UpdateRegistry::getRemovedPostUpdates() Fixed

To add performance testing for this we'd need to be able to count function calls via zend_observer which requires a PHP extension. This is not out of the question and something I'd love us to be able to do eventually, but it'd be a completely new thing compared to the current performance testing and quite a lot of work to set up.

Steps to reproduce

NA

Proposed resolution

TBD

Merge request link

Remaining tasks

Determine firs tsteps

User interface changes

TBD

API changes

TBD

Data model changes

TBD

Release notes snippet

TBD