feat: custom apm

[buenaflor]

📜 Description

Adds feature to create spans and configure tracesSampler

💡 Motivation and Context

Closes #83

💚 How did you test it?

Example app
Tests

📝 Checklist

You have to check all boxes before merging:

• I reviewed the submitted code.
• 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.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.

🔮 Next steps

[github-actions]

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

Generated by 🚫 dangerJS against 2b27001

[buenaflor]

validating it works from demo app

[codecov]

Codecov Report

Attention: 60 lines in your changes are missing coverage. Please review.

Comparison is base (fb911de) 77.83% compared to head (2b27001) 74.95%.
Report is 15 commits behind head on main.

Files	Patch %	Lines
...ltiplatform/converters/SpanStatusConverters.jvm.kt	11.76%	28 Missing and 2 partials ⚠️
...io/sentry/kotlin/multiplatform/SentryBridge.jvm.kt	62.06%	10 Missing and 1 partial ⚠️
.../converters/TransactionNameSourceConverters.jvm.kt	14.28%	5 Missing and 1 partial ⚠️
.../converters/CustomSamplingContextConverters.jvm.kt	0.00%	5 Missing ⚠️
...in/multiplatform/TransactionContextProvider.jvm.kt	75.00%	2 Missing and 1 partial ⚠️
.../io/sentry/kotlin/multiplatform/SpanAdapter.jvm.kt	90.47%	0 Missing and 2 partials ⚠️
...orm/converters/TransactionContextConverters.jvm.kt	85.71%	0 Missing and 1 partial ⚠️
...platform/extensions/SentryOptionsExtensions.jvm.kt	85.71%	0 Missing and 1 partial ⚠️
...kotlin/io/sentry/kotlin/multiplatform/SentryKMP.kt	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #155      +/-   ##
==========================================
- Coverage   77.83%   74.95%   -2.88%     
==========================================
  Files          27       38      +11     
  Lines         424      615     +191     
  Branches       55       75      +20     
==========================================
+ Hits          330      461     +131     
- Misses         68      119      +51     
- Partials       26       35       +9     

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[buenaflor]

After discussion we will reconsider the approach of using the native layer directly and keep performance related product withing the cross-platform layer.

[XanderZhu]

Will this functionality ever be ready? I really need the ability to measure the waiting time of requests on the client side.

[buenaflor]

@XanderZhu

hey so far we have not planned to continue this feature, at least not until we have enough interest from other people.

But it's helpful that you show your interest here so we can re-prio this.

I have shared an example code snippet so you can start custom instrumenting on your own: #83 (comment)

[XanderZhu]

@buenaflor
Thnx for the shared code snippet. That's enough for my use case.