fix: Add app start to first finished transaction

[philipphofmann]

📜 Description

The SDK added the app start measurement and spans to the first finished auto-generated UIViewController transaction. The first finished UIViewController transaction is not necessarily the transaction of the first loaded screen. As auto-generated transactions for UIViewControllers wait for all children to finish, it may kick off, for example, a web request that lasts for a couple of seconds in the background. In the meantime, the user navigates to another screen, which finishes loading before the web request. The SDK added the app start data to the wrong transaction in such an edge case. This is fixed now by adding the app start data to the first started transaction.

💡 Motivation and Context

Fixes GH-2248

💚 How did you test it?

Unit tests and on a real device with the steps described in GH-2248.

LoremIpsumViewController without the app start data.

iOS_Swift.ViewController with the app start data

📝 Checklist

• I reviewed the submitted code
• I added tests to verify the changes
• I updated the docs if needed
• Review from the native team if needed
• No breaking changes

🔮 Next steps

[brustolin]

I see what you did here 😁👏🏻...

[brustolin]

LGTM

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1251.08 ms	1252.94 ms	1.86 ms
Size	20.51 KiB	333.58 KiB	313.07 KiB

Baseline results on branch: master

Startup times

Revision	Plain	With Sentry	Diff
e2f1150	1220.39 ms	1249.94 ms	29.55 ms
ee127f4	1203.49 ms	1231.28 ms	27.79 ms
4a66f00	1259.84 ms	1281.66 ms	21.82 ms
864c39a	1191.14 ms	1233.38 ms	42.24 ms
b172a8b	1257.68 ms	1272.38 ms	14.70 ms
4a66f00	1224.73 ms	1241.14 ms	16.41 ms
864c39a	1239.45 ms	1256.76 ms	17.31 ms
347a8e9	1243.50 ms	1265.90 ms	22.40 ms
e958899	1230.40 ms	1248.31 ms	17.91 ms
a5ca27b	1231.31 ms	1252.56 ms	21.25 ms

App size

Revision	Plain	With Sentry	Diff
e2f1150	20.51 KiB	333.10 KiB	312.59 KiB
ee127f4	20.51 KiB	333.10 KiB	312.59 KiB
4a66f00	20.51 KiB	331.79 KiB	311.28 KiB
864c39a	20.51 KiB	335.57 KiB	315.06 KiB
b172a8b	20.51 KiB	331.79 KiB	311.28 KiB
4a66f00	20.51 KiB	331.79 KiB	311.28 KiB
864c39a	20.51 KiB	335.57 KiB	315.06 KiB
347a8e9	20.51 KiB	333.16 KiB	312.65 KiB
e958899	20.51 KiB	331.92 KiB	311.41 KiB
a5ca27b	20.51 KiB	331.81 KiB	311.31 KiB

Previous results on branch: fix/app-start-on-first-finished-transaction

Startup times

Revision	Plain	With Sentry	Diff
d8176b6	1223.71 ms	1258.48 ms	34.77 ms
b00b932	1209.52 ms	1242.17 ms	32.65 ms
667289c	1217.00 ms	1230.14 ms	13.14 ms
1963019	1259.18 ms	1267.12 ms	7.94 ms
5bcd104	1246.86 ms	1263.78 ms	16.92 ms
e85c3b9	1239.02 ms	1246.06 ms	7.04 ms

App size

Revision	Plain	With Sentry	Diff
d8176b6	20.51 KiB	333.09 KiB	312.58 KiB
b00b932	20.51 KiB	333.08 KiB	312.57 KiB
667289c	20.51 KiB	333.08 KiB	312.57 KiB
1963019	20.51 KiB	333.09 KiB	312.58 KiB
5bcd104	20.51 KiB	333.09 KiB	312.58 KiB
e85c3b9	20.51 KiB	333.09 KiB	312.58 KiB