perf(core): Detect Sentry executor thread without a name scan

[runningcode]

Resolves JAVA-607.

Description

PersistingScopeObserver.serializeToDisk decided whether it was already on the Sentry executor thread by scanning the thread name:

if (Thread.currentThread().getName().contains("SentryExecutor")) { ... }

Thread.getName() allocates a fresh String and .contains() scans it — on every scope mutation (breadcrumb, tag, trace, user, …), including on the main thread as the synchronous part of addBreadcrumb.

This tags the executor threads with a package-private marker Thread subclass (thread name unchanged) and adds an allocation-free SentryExecutorService.isSentryExecutorThread() check used in its place.

API

Adds one method to the already @ApiStatus.Internal SentryExecutorService; apiDump regenerated (single-line .api addition).

Source

Found via on-device Perfetto method-trace analysis of the Android SDK scope-persistence path (~3,130 scope stores go through this gate). Part of Reduce SDK init time [Android].

🤖 Generated with Claude Code

[linear-code]

JAVA-607

[sentry]

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
SDK Size	io.sentry.tests.size	8.47.0 (1)	release

⚙️ sentry-android Build Distribution Settings

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	317.56 ms	361.66 ms	44.10 ms
Size	0 B	0 B	0 B

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
abfcc92	304.04 ms	370.33 ms	66.29 ms
4e3e79d	365.83 ms	477.62 ms	111.79 ms
d8912da	329.94 ms	389.68 ms	59.74 ms
d15471f	294.13 ms	399.49 ms	105.36 ms
abf451a	332.82 ms	403.67 ms	70.85 ms
604a261	380.65 ms	451.27 ms	70.62 ms
806307f	357.85 ms	424.64 ms	66.79 ms
22f4345	307.87 ms	354.51 ms	46.64 ms
d217708	375.27 ms	415.68 ms	40.41 ms
c3ee041	310.64 ms	361.90 ms	51.26 ms

App size

Revision	Plain	With Sentry	Diff
abfcc92	1.58 MiB	2.13 MiB	557.31 KiB
4e3e79d	0 B	0 B	0 B
d8912da	0 B	0 B	0 B
d15471f	1.58 MiB	2.13 MiB	559.54 KiB
abf451a	1.58 MiB	2.20 MiB	635.29 KiB
604a261	1.58 MiB	2.10 MiB	533.42 KiB
806307f	1.58 MiB	2.10 MiB	533.42 KiB
22f4345	1.58 MiB	2.29 MiB	719.83 KiB
d217708	1.58 MiB	2.10 MiB	532.97 KiB
c3ee041	0 B	0 B	0 B