feat(extend-app-start): [4/4] Add public Sentry app start extension API

[buenaflor]

PR Stack (Extend App Start)

• feat(extend-app-start): App start extension API #5604
• feat(extend-app-start): [1/4] Add IAppStartExtender bridge #5605
• feat(extend-app-start): [2/4] Extract AppStartExtension component #5606
• feat(extend-app-start): [3/4] Eagerly create the extended app start transaction #5608
• feat(extend-app-start): [4/4] Add public Sentry app start extension API #5628

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📜 Description

Adds the public static facade for the app start extension API — the only PR in the stack that adds public API surface. Each method is a thin bridge to getCurrentScopes().getOptions().getAppStartExtender() (the IAppStartExtender from [1/4]), mirroring Sentry.reportFullyDisplayed().

Method	Purpose
Sentry.extendAppStart()	Begin extending the app start (call from Application.onCreate, right after SentryAndroid.init).
Sentry.getExtendedAppStartSpan()	The extended ISpan to attach child spans to — or a NoOpSpan when no extension is active.
Sentry.finishExtendedAppStart()	Finish the extension, letting the app start transaction complete.

No-op when the SDK is disabled, on platforms without an app start extender, or when standalone app start tracing is off.

Also adds a usage example to the Android sample (MyApplication): extendAppStart(), child spans under getExtendedAppStartSpan(), then finishExtendedAppStart().

💡 Motivation and Context

Fourth and final PR of the app start extension API stack (#5553), which lets apps extend the app start measurement to cover extra launch-time work — e.g. loading remote config before the first screen (mirrors sentry-cocoa's extendAppLaunch() / finishExtendedAppLaunch()).

💚 How did you test it?

SentryTest verifies the three methods delegate to options.getAppStartExtender(), and that the API returns a no-op span / no-ops when the SDK is disabled. apiCheck, spotless, and the :sentry unit suite pass; the sample module compiles.

📝 Checklist

• I added GH Issue ID & Linear ID
• 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.

🔮 Next steps

Final PR of the stack. Once the stack is merged up, the collection branch (#5604) squash-merges into main.

⚠️ Merge this PR using a merge commit (not squash). Only the collection branch is squash-merged into main.

#skip-changelog

[github-actions]

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

Generated by 🚫 dangerJS against caa7945

[sentry]

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
SDK Size	io.sentry.tests.size	8.44.1 (1)	release

⚙️ sentry-android Build Distribution Settings

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	353.34 ms	419.94 ms	66.60 ms
Size	0 B	0 B	0 B

Baseline results on branch: feat/app-start-extension-materialize

Startup times

Revision	Plain	With Sentry	Diff
4cf89ba	340.51 ms	416.92 ms	76.41 ms
4451634	321.21 ms	376.21 ms	55.00 ms
20bbe9a	305.48 ms	387.25 ms	81.77 ms
69caaee	313.73 ms	373.92 ms	60.19 ms

App size

Revision	Plain	With Sentry	Diff
4cf89ba	0 B	0 B	0 B
4451634	0 B	0 B	0 B
20bbe9a	0 B	0 B	0 B
69caaee	0 B	0 B	0 B

Previous results on branch: feat/app-start-extension-api

Startup times

Revision	Plain	With Sentry	Diff
d35892b	313.39 ms	367.63 ms	54.25 ms
097718d	323.29 ms	363.42 ms	40.13 ms

App size

Revision	Plain	With Sentry	Diff
d35892b	0 B	0 B	0 B
097718d	0 B	0 B	0 B

[Copilot]

Pull request overview

Adds a public static facade on io.sentry.Sentry for the Android app start extension feature, exposing a small public API surface that delegates to the internally-wired IAppStartExtender in SentryOptions.

Changes:

• Added Sentry.extendAppStart(), Sentry.finishExtendedAppStart(), and Sentry.getExtendedAppStartSpan() as public entry points delegating to getCurrentScopes().getOptions().getAppStartExtender().
• Added unit tests ensuring the new methods delegate correctly and remain no-ops when the SDK is disabled.
• Added an Android sample usage demonstrating extending app start and creating child spans under the extended app start span.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
sentry/src/main/java/io/sentry/Sentry.java	Introduces the new public facade methods and Javadoc for the app start extension API.
sentry/src/test/java/io/sentry/SentryTest.kt	Adds delegation + disabled-SDK no-op coverage for the new public facade methods.
sentry/api/sentry.api	Updates the API surface dump to include the newly added Sentry methods.
sentry-samples/sentry-samples-android/src/main/java/io/sentry/samples/android/MyApplication.java	Demonstrates intended usage of the new API in the Android sample app.

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