feat: use addTimingsCallback instead of addPostFrameCallback to determine app start end

[buenaflor]

📜 Description

Improve app start measurements

💡 Motivation and Context

The addTimingsCallback contains the accurate data for the first frame unlike addPostFramecallback which is not correct as it depends on when SentryFlutter.init is called

addTimingsCallback is always reported immediately for the first frame so it's very suitable to use here, see https://api.flutter.dev/flutter/scheduler/SchedulerBinding/addTimingsCallback.html

💚 How did you test it?

Unit tests, manual tests

📝 Checklist

• I reviewed submitted code
• I added tests to verify changes
• No new PII added or SDK only sends newly added PII if sendDefaultPii is enabled
• I updated the docs if needed
• All tests passing
• No breaking changes

🔮 Next steps

[github-actions]

🚨 Detected changes in high risk code 🚨

High-risk code has higher potential to break the SDK and may be hard to test. To prevent severe bugs, apply the rollout process for releasing such changes and be extra careful when changing and reviewing these files:

• flutter/lib/src/integrations/native_app_start_integration.dart

[github-actions]

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

Generated by 🚫 dangerJS against f993041

[codecov]

Codecov Report

Attention: Patch coverage is 92.30769% with 1 line in your changes missing coverage. Please review.

Project coverage is 86.05%. Comparing base (404f5a9) to head (f993041).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
flutter/lib/src/frame_callback_handler.dart	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2405      +/-   ##
==========================================
+ Coverage   85.04%   86.05%   +1.00%     
==========================================
  Files         257       81     -176     
  Lines        9194     2875    -6319     
==========================================
- Hits         7819     2474    -5345     
+ Misses       1375      401     -974     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

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🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests

[github-actions]

Android Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	459.28 ms	540.31 ms	81.02 ms
Size	6.49 MiB	7.56 MiB	1.07 MiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
453e1bc	320.41 ms	372.73 ms	52.32 ms
061fed2	434.11 ms	506.49 ms	72.38 ms
9928a74	375.26 ms	456.30 ms	81.04 ms
11fb408	320.10 ms	380.24 ms	60.14 ms
dd76eef	461.37 ms	540.55 ms	79.18 ms
2261c15	370.00 ms	455.88 ms	85.88 ms
d089990	361.67 ms	442.50 ms	80.83 ms
ca7f531	395.69 ms	497.82 ms	102.12 ms
e5b744f	302.70 ms	342.17 ms	39.47 ms
1e094d3	316.22 ms	378.69 ms	62.47 ms

App size

Revision	Plain	With Sentry	Diff
453e1bc	5.94 MiB	6.95 MiB	1.01 MiB
061fed2	6.52 MiB	7.59 MiB	1.06 MiB
9928a74	5.94 MiB	6.96 MiB	1.02 MiB
11fb408	6.06 MiB	7.10 MiB	1.04 MiB
dd76eef	6.35 MiB	7.40 MiB	1.05 MiB
2261c15	6.27 MiB	7.20 MiB	957.75 KiB
d089990	6.34 MiB	7.28 MiB	967.79 KiB
ca7f531	6.33 MiB	7.26 MiB	949.75 KiB
e5b744f	6.06 MiB	7.09 MiB	1.03 MiB
1e094d3	6.16 MiB	7.14 MiB	1004.21 KiB

Previous results on branch: enh/app-start-time

Startup times

Revision	Plain	With Sentry	Diff
21acda1	450.35 ms	492.31 ms	41.96 ms
92b5b84	453.60 ms	485.92 ms	32.32 ms
5990562	463.09 ms	508.14 ms	45.05 ms
ca24b53	475.92 ms	551.68 ms	75.76 ms
b1e9b9c	469.20 ms	500.98 ms	31.78 ms
803684b	455.88 ms	497.16 ms	41.29 ms
d724aac	482.20 ms	512.35 ms	30.14 ms
4def0ce	465.86 ms	494.74 ms	28.88 ms
9be4829	438.42 ms	458.45 ms	20.03 ms
88bc8a5	482.94 ms	515.82 ms	32.88 ms

App size

Revision	Plain	With Sentry	Diff
21acda1	6.49 MiB	7.56 MiB	1.07 MiB
92b5b84	6.49 MiB	7.56 MiB	1.07 MiB
5990562	6.49 MiB	7.56 MiB	1.07 MiB
ca24b53	6.49 MiB	7.56 MiB	1.07 MiB
b1e9b9c	6.49 MiB	7.56 MiB	1.07 MiB
803684b	6.49 MiB	7.56 MiB	1.07 MiB
d724aac	6.49 MiB	7.56 MiB	1.07 MiB
4def0ce	6.49 MiB	7.56 MiB	1.07 MiB
9be4829	6.49 MiB	7.56 MiB	1.07 MiB
88bc8a5	6.49 MiB	7.56 MiB	1.07 MiB

[buenaflor]

cc @stefanosiano @denrase please take a look

[denrase]

Looking good. Only had 2 comment, but those cases work fine when i tested in the example app. 👍

[github-actions]

iOS Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1254.24 ms	1274.58 ms	20.34 ms
Size	8.38 MiB	9.77 MiB	1.40 MiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
824df58	1235.72 ms	1259.02 ms	23.30 ms
3f3ef0b	1223.73 ms	1237.67 ms	13.94 ms
4c78360	1230.35 ms	1252.37 ms	22.01 ms
ca9f398	1227.29 ms	1236.20 ms	8.92 ms
dd933d4	1238.73 ms	1252.43 ms	13.70 ms
afa6e2a	1251.04 ms	1266.65 ms	15.61 ms
a49594a	1284.83 ms	1313.29 ms	28.45 ms
a094100	1260.27 ms	1276.75 ms	16.48 ms
8fa3934	1252.79 ms	1272.41 ms	19.62 ms
613760b	1263.10 ms	1277.27 ms	14.16 ms

App size

Revision	Plain	With Sentry	Diff
824df58	8.33 MiB	9.64 MiB	1.31 MiB
3f3ef0b	8.32 MiB	9.38 MiB	1.05 MiB
4c78360	8.32 MiB	9.38 MiB	1.06 MiB
ca9f398	8.38 MiB	9.74 MiB	1.36 MiB
dd933d4	8.33 MiB	9.64 MiB	1.31 MiB
afa6e2a	8.28 MiB	9.33 MiB	1.05 MiB
a49594a	8.16 MiB	9.16 MiB	1.00 MiB
a094100	8.16 MiB	9.17 MiB	1.01 MiB
8fa3934	8.09 MiB	9.07 MiB	1000.86 KiB
613760b	8.15 MiB	9.13 MiB	1000.46 KiB

Previous results on branch: enh/app-start-time

Startup times

Revision	Plain	With Sentry	Diff
d724aac	1246.35 ms	1271.84 ms	25.48 ms
9be4829	1224.19 ms	1243.20 ms	19.01 ms
b1e9b9c	1252.49 ms	1273.52 ms	21.03 ms
803684b	1253.82 ms	1263.78 ms	9.96 ms
34988b1	1252.16 ms	1268.30 ms	16.13 ms
5990562	1245.67 ms	1275.57 ms	29.90 ms
4def0ce	1252.67 ms	1274.83 ms	22.16 ms
1fec51e	1243.58 ms	1275.52 ms	31.94 ms
92b5b84	1233.21 ms	1244.96 ms	11.75 ms
88bc8a5	1242.29 ms	1264.04 ms	21.75 ms

App size

Revision	Plain	With Sentry	Diff
d724aac	8.38 MiB	9.77 MiB	1.40 MiB
9be4829	8.38 MiB	9.77 MiB	1.40 MiB
b1e9b9c	8.38 MiB	9.77 MiB	1.40 MiB
803684b	8.38 MiB	9.77 MiB	1.40 MiB
34988b1	8.38 MiB	9.77 MiB	1.40 MiB
5990562	8.38 MiB	9.77 MiB	1.40 MiB
4def0ce	8.38 MiB	9.77 MiB	1.40 MiB
1fec51e	8.38 MiB	9.77 MiB	1.40 MiB
92b5b84	8.38 MiB	9.77 MiB	1.40 MiB
88bc8a5	8.38 MiB	9.77 MiB	1.40 MiB