fix(performance): app start frames can start with zeroed values

[krystofwoldrich]

📢 Type of change

• Bugfix

📜 Description

The native implementations dropped zero value measurements, which could cause app start frames not to be measured as frames on transaction start would be null.

This PR change native impls to return zero values and adds zero value check to processing final frames.

💚 How did you test it?

sample app, unit 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
• All tests passing
• No breaking changes

[github-actions]

Android (legacy) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	483.70 ms	508.35 ms	24.65 ms
Size	17.73 MiB	19.94 MiB	2.21 MiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
8900e1a+dirty	430.68 ms	456.13 ms	25.44 ms
d361d38	354.10 ms	381.69 ms	27.59 ms
9c48b2c	349.24 ms	385.96 ms	36.72 ms
9a3ca65+dirty	326.93 ms	330.14 ms	3.21 ms
d197b5c+dirty	338.94 ms	354.87 ms	15.93 ms
457e29f	398.10 ms	421.39 ms	23.29 ms
e5c9b8b	409.02 ms	426.66 ms	17.64 ms
5bb8d5f	431.21 ms	459.40 ms	28.19 ms
31fcca2	391.22 ms	414.78 ms	23.56 ms
abb7058	370.27 ms	389.58 ms	19.31 ms

App size

Revision	Plain	With Sentry	Diff
8900e1a+dirty	17.73 MiB	19.75 MiB	2.01 MiB
d361d38	17.73 MiB	19.81 MiB	2.08 MiB
9c48b2c	17.73 MiB	19.80 MiB	2.07 MiB
9a3ca65+dirty	17.73 MiB	20.04 MiB	2.31 MiB
d197b5c+dirty	17.73 MiB	20.04 MiB	2.31 MiB
457e29f	17.73 MiB	19.84 MiB	2.10 MiB
e5c9b8b	17.73 MiB	19.83 MiB	2.10 MiB
5bb8d5f	17.73 MiB	19.93 MiB	2.20 MiB
31fcca2	17.73 MiB	19.90 MiB	2.17 MiB
abb7058	17.73 MiB	19.83 MiB	2.10 MiB

[github-actions]

iOS (new) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1223.47 ms	1227.09 ms	3.62 ms
Size	2.92 MiB	3.59 MiB	686.60 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
34aba08+dirty	1268.58 ms	1276.80 ms	8.22 ms
1d86dd6+dirty	1289.25 ms	1293.36 ms	4.11 ms
abb7058+dirty	1260.28 ms	1266.56 ms	6.28 ms
70caa60+dirty	1279.08 ms	1281.54 ms	2.46 ms
e73f4ed+dirty	1282.90 ms	1309.30 ms	26.40 ms
22e31b6+dirty	1276.55 ms	1278.12 ms	1.57 ms
27ef4ee+dirty	1236.41 ms	1244.90 ms	8.49 ms
8900e1a+dirty	1268.36 ms	1273.04 ms	4.68 ms
5bb8d5f+dirty	1215.04 ms	1217.52 ms	2.48 ms
6e8584e+dirty	1271.71 ms	1281.26 ms	9.55 ms

App size

Revision	Plain	With Sentry	Diff
34aba08+dirty	2.92 MiB	3.41 MiB	499.03 KiB
1d86dd6+dirty	2.92 MiB	3.44 MiB	538.27 KiB
abb7058+dirty	2.92 MiB	3.43 MiB	524.53 KiB
70caa60+dirty	2.92 MiB	3.39 MiB	486.04 KiB
e73f4ed+dirty	2.92 MiB	3.38 MiB	475.71 KiB
22e31b6+dirty	2.92 MiB	3.43 MiB	524.74 KiB
27ef4ee+dirty	2.92 MiB	3.41 MiB	503.72 KiB
8900e1a+dirty	2.92 MiB	3.39 MiB	485.96 KiB
5bb8d5f+dirty	2.92 MiB	3.48 MiB	575.85 KiB
6e8584e+dirty	2.92 MiB	3.44 MiB	536.52 KiB

[lucas-zimerman]

LGTM!

[github-actions]

iOS (legacy) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1224.58 ms	1225.80 ms	1.22 ms
Size	2.36 MiB	3.03 MiB	680.87 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
34aba08+dirty	1276.78 ms	1308.52 ms	31.74 ms
1d86dd6+dirty	1249.71 ms	1279.16 ms	29.45 ms
abb7058+dirty	1255.42 ms	1268.86 ms	13.44 ms
70caa60+dirty	1218.27 ms	1230.30 ms	12.03 ms
e73f4ed+dirty	1243.27 ms	1244.52 ms	1.25 ms
22e31b6+dirty	1253.62 ms	1265.96 ms	12.34 ms
27ef4ee+dirty	1293.52 ms	1296.08 ms	2.56 ms
8900e1a+dirty	1210.27 ms	1218.66 ms	8.39 ms
5bb8d5f+dirty	1235.47 ms	1237.39 ms	1.92 ms
6e8584e+dirty	1274.50 ms	1296.82 ms	22.32 ms

App size

Revision	Plain	With Sentry	Diff
34aba08+dirty	2.36 MiB	2.85 MiB	495.32 KiB
1d86dd6+dirty	2.36 MiB	2.89 MiB	535.43 KiB
abb7058+dirty	2.36 MiB	2.87 MiB	520.42 KiB
70caa60+dirty	2.36 MiB	2.83 MiB	479.27 KiB
e73f4ed+dirty	2.36 MiB	2.82 MiB	469.44 KiB
22e31b6+dirty	2.36 MiB	2.87 MiB	520.67 KiB
27ef4ee+dirty	2.36 MiB	2.85 MiB	500.03 KiB
8900e1a+dirty	2.36 MiB	2.83 MiB	479.25 KiB
5bb8d5f+dirty	2.36 MiB	2.92 MiB	570.22 KiB
6e8584e+dirty	2.36 MiB	2.88 MiB	533.17 KiB