WIP: feat(profiling): track profiler overhead

[realFlowControl]

Description

This PR aims to track the overhead of profiling.
This is currently in PoC phase 😉

Readiness checklist

• (only for Members) Changelog has been added to the release document.
• Tests added for this feature/bug.

Reviewer checklist

• Appropriate labels assigned.
• Milestone is set.
• Changelog has been added to the release document. For community contributors the reviewer is in charge of this task.

[morrisonlevi]

Why is there a new sample type rather than putting them into timeline?

[realFlowControl]

I'm just playing with ideas currently. Instead of adding a new sample for every sample that we create we might be able to attach to the sample currently created, which means we are not doubling the number of samples. It has some drawbacks, as we do not measure the entire round trip and we are for example missing the time it takes to try_send() the sample to the other thread.
We are btw. still able to surface these in the timeline, even when the times are in another sample type

[pr-commenter]

Benchmarks

Benchmark execution time: 2023-11-08 15:47:48

Comparing candidate commit 78bce3b in PR branch florian/track-overhead with baseline commit a1f35f6 in branch master.

Found 0 performance improvements and 2 performance regressions! Performance is the same for 16 metrics, 3 unstable metrics.

scenario:php-profiler-timeline-memory-with-profiler-and-timeline

• 🟥 max_rss_usage [+1.468MB; +1.764MB] or [+5.064%; +6.086%]

scenario:walk_stack/1

• 🟥 wall_time [+280.727ns; +284.433ns] or [+2.310%; +2.341%]