Add Ktor client integration

[lcian]

📜 Description

Add a Ktor client integration.
Functionality, options and tests are similar to our OkHttp integration.

💡 Motivation and Context

Part of #2684

💚 How did you test it?

End to end and manual tests

📝 Checklist

• 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

• Changelog
• Docs feat(android/java): document Ktor Client integration sentry-docs#14457
• Readme
• Add module to main readme
• Release
• Add module to .craft.yml Add sentry-ktor-client to .craft.yml #4589
• Add module to release registry feat: Add sentry-ktor-client for Android/Java sentry-release-registry#204
• e2e tests

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	417.00 ms	447.33 ms	30.33 ms
Size	1.58 MiB	2.09 MiB	519.49 KiB

Previous results on branch: lcian/feat/ktor-client

Startup times

Revision	Plain	With Sentry	Diff
94e993e	404.49 ms	439.62 ms	35.13 ms
df1fbd1	407.84 ms	424.93 ms	17.09 ms
b5f9205	492.51 ms	542.98 ms	50.47 ms
569c88a	406.86 ms	419.57 ms	12.72 ms
9647976	403.48 ms	420.36 ms	16.88 ms
1df63ce	429.52 ms	485.02 ms	55.50 ms
e2d324e	400.33 ms	423.66 ms	23.33 ms
c3b3ac8	433.74 ms	490.08 ms	56.34 ms
f316c06	427.39 ms	464.94 ms	37.55 ms
bc4c3ab	420.27 ms	462.92 ms	42.65 ms

App size

Revision	Plain	With Sentry	Diff
94e993e	1.58 MiB	2.09 MiB	519.31 KiB
df1fbd1	1.58 MiB	2.09 MiB	519.08 KiB
b5f9205	1.58 MiB	2.09 MiB	519.31 KiB
569c88a	1.58 MiB	2.09 MiB	519.08 KiB
9647976	1.58 MiB	2.09 MiB	519.31 KiB
1df63ce	1.58 MiB	2.09 MiB	518.90 KiB
e2d324e	1.58 MiB	2.09 MiB	519.49 KiB
c3b3ac8	1.58 MiB	2.09 MiB	518.90 KiB
f316c06	1.58 MiB	2.09 MiB	519.08 KiB
bc4c3ab	1.58 MiB	2.09 MiB	518.90 KiB

[lcian]

@romtsn Please let me know what you think about this approach: 8a42315 (#4527)
As far as I can tell it's not possible to do this without reflection, as the config property has internal visibility.
I've also added a ProGuard rule that should ensure this works when ProGuard is being used, as we rely on those class/property names.

The approach is still not perfect because if the config block has some side effects, we would trigger them when creating the fake client.
However this seems to be the only approach to do this successfully.
Otherwise I guess another option would be to somehow detect the usage of OkHttp as engine for Ktor and conditionally disable the instrumentation in SAGP, and leave the responsibility to the user to not double instrument when not using SAGP.

As a next step I want to set up an app using ProGuard and SAGP to ensure this works as intended.

[lcian]

I've set up an Android sample with SAGP and it seems this approach to detect our OkHttp instrumentation doesn't work. As far as I understand, that's because the bytecode manipulation only adds the interceptor when we're in okhttp3.internal.connection.RealCall::getResponseWithInterceptorChain, so it cannot be detected outside of that method.

[lcian]

The OkHttp instrumentation is automatically added by SAGP, but users would have to manually set up this Ktor integration.
So I think a viable option would be to just state very clearly in the docs that if you're using OkHttp as the engine and already using the OkHttp integration or SAGP with auto instrumentation enabled, you should not use the Ktor plugin.
What do you think @romtsn ?

[romtsn]

The OkHttp instrumentation is automatically added by SAGP, but users would have to manually set up this Ktor integration. So I think a viable option would be to just state very clearly in the docs that if you're using OkHttp as the engine and already using the OkHttp integration or SAGP with auto instrumentation enabled, you should not use the Ktor plugin. What do you think @romtsn ?

oh dang, sorry I made you go through this. Yeah, this sounds like a job for the gradle plugin to do. Could you file an issue there please? And highlighting this in the docs for now sounds good too 👍

[lcian]

Okay, opened the issue in SAGP: getsentry/sentry-android-gradle-plugin#949
Tested with a sample app and functionality looks good.
I'm going to prepare docs and then merge this.

[adinauer]

LGTM one question about reported integration name.

[github-actions]

	Fails
🚫	Please consider adding a changelog entry for the next release.

Instructions and example for changelog

Please add an entry to CHANGELOG.md to the "Unreleased" section. Make sure the entry includes this PR's number.

Example:

## Unreleased

- Add Ktor client integration ([#4527](https://github.com/getsentry/sentry-java/pull/4527))

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