feat(session-replay): add preferred frame rate to display link wrapper

[philprime]

📜 Description

Configures the CADisplayLink used by session replay to use the target frame rate

💡 Motivation and Context

If the display link is not configured with a target frame rate, it can cause apps to run at 60 FPS even if not necessary.

💚 How did you test it?

Ran the sample app and checked created frames

📝 Checklist

You have to check all boxes before merging:

• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• I updated the wizard if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

[github-actions]

	Fails
🚫	Please consider adding a changelog entry for the next release.

	Messages
📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Instructions and example for changelog

Please add an entry to CHANGELOG.md to the "Unreleased" section. Make sure the entry includes this PR's number.

Example:

## Unreleased

- add preferred frame rate to display link wrapper ([#5258](https://github.com/getsentry/sentry-cocoa/pull/5258))

If none of the above apply, you can opt out of this check by adding #skip-changelog to the PR description.

Generated by 🚫 dangerJS against b94ef04

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 25 lines in your changes missing coverage. Please review.

Project coverage is 9.172%. Comparing base (e70c3aa) to head (b94ef04).
Report is 20 commits behind head on main.

Files with missing lines	Patch %	Lines
...tegrations/SessionReplay/SentrySessionReplay.swift	0.000%	16 Missing ⚠️
Sources/Sentry/include/SentryDisplayLinkWrapper.m	0.000%	6 Missing ⚠️
Sources/Sentry/SentryFramesTracker.m	0.000%	3 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (e70c3aa) and HEAD (b94ef04). Click for more details.

HEAD has 3 uploads less than BASE

Flag	BASE (e70c3aa)	HEAD (b94ef04)
	4	1

Additional details and impacted files

@@              Coverage Diff              @@
##              main    #5258        +/-   ##
=============================================
- Coverage   92.893%   9.172%   -83.721%     
=============================================
  Files          689      363       -326     
  Lines        86259    26535     -59724     
  Branches     31221      121     -31100     
=============================================
- Hits         80129     2434     -77695     
- Misses        6028    24101     +18073     
+ Partials       102        0       -102     

Files with missing lines	Coverage Δ
Sources/Sentry/SentryFramesTracker.m	17.142% <0.000%> (-82.375%)	⬇️
Sources/Sentry/include/SentryDisplayLinkWrapper.m	0.000% <0.000%> (-100.000%)	⬇️
...tegrations/SessionReplay/SentrySessionReplay.swift	0.000% <0.000%> (-90.554%)	⬇️

... and 677 files with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e70c3aa...b94ef04. Read the comment docs.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1232.82 ms	1259.96 ms	27.14 ms
Size	23.76 KiB	820.87 KiB	797.11 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
2f8b3a8	1233.76 ms	1260.24 ms	26.48 ms
5e66a38	1209.10 ms	1233.90 ms	24.79 ms
94e1968	1238.85 ms	1252.02 ms	13.17 ms
d011484	1220.86 ms	1237.18 ms	16.33 ms
f0737f6	1220.43 ms	1236.44 ms	16.01 ms
324dc7b	1210.33 ms	1244.92 ms	34.59 ms
79239ff	1223.53 ms	1250.98 ms	27.45 ms
f278bab	1236.50 ms	1251.75 ms	15.25 ms
84fb4d9	1212.45 ms	1223.39 ms	10.94 ms
f938d24	1223.26 ms	1242.12 ms	18.86 ms

App size

Revision	Plain	With Sentry	Diff
2f8b3a8	20.76 KiB	434.72 KiB	413.96 KiB
5e66a38	22.85 KiB	408.88 KiB	386.03 KiB
94e1968	21.58 KiB	614.74 KiB	593.16 KiB
d011484	21.58 KiB	616.14 KiB	594.56 KiB
f0737f6	20.76 KiB	437.12 KiB	416.36 KiB
324dc7b	22.85 KiB	408.84 KiB	385.99 KiB
79239ff	22.31 KiB	765.78 KiB	743.46 KiB
f278bab	22.31 KiB	760.65 KiB	738.33 KiB
84fb4d9	22.84 KiB	402.56 KiB	379.72 KiB
f938d24	20.76 KiB	434.88 KiB	414.12 KiB

[philipphofmann]

If the display link is not configured with a target frame rate, it can cause apps to run at 60 FPS even if not necessary.

Can you prove this? How can we be sure that's the case? According to a recent investigation of @noahsmartin we should actually swap out the CADisplayLink and use a RunLoopObserver instead; see internal Notion doc. I think it makes sense to decide on our future approach before touching this right now.

[philprime]

Can you prove this?
I observed this behavior during testing of #4940 that the sample app starts off with less than 60 FPS frame rate, then when SR starts it spins up to 60 FPS. But it could also be caused from unoptimized

I would have to create a reproducible project to proof this with numbers, but I believe the documentation [1] states enough reason for this change:

Use lower refresh rates whenever possible to save power, because higher refresh rates can result in significant power consumption.

• [1] https://developer.apple.com/documentation/quartzcore/optimizing-promotion-refresh-rates-for-iphone-13-pro-and-ipad-pro#Enable-faster-ProMotion-refresh-rates

According to a recent investigation of @noahsmartin we should actually swap out the CADisplayLink and use a RunLoopObserver instead; see internal Notion doc. I think it makes sense to decide on our future approach before touching this right now.

I agree with swapping it out for performance tracing, I am not convinced yet that it is the right approach for visual timers and per-frame updates. We need to ensure that we do get the target frame rate, as we are trying to achieve constant FPS. This is out-of-scope for this PR.

[philipphofmann]

As discussed in an internal meeting, I think I wouldn't change the preferred frame rate for SR right now. I think we first should investigate #5263 before tackling this PR.