Preserve caller context at async request dispatch

[sylvesterkaczmarek]

Summary

Fixes #952.

Remove the unconditional common-pool hop between request preparation and asynchronous transport entry at all 295 dispatch sites. The configured transport can now capture the caller's context before scheduling HTTP work. Network I/O and stream callbacks retain their existing executors; no new executor, option, or dependency is introduced.

Regression coverage exercises typed and raw responses, the synchronous client's async view, configured and explicit stream callback executors, pending response futures, and synchronous/asynchronous transport failures.

Execution boundary

Synchronous setup inside HttpClient.executeAsync now runs on the request-preparation completion thread. Transports remain responsible for offloading blocking I/O. This does not add general context propagation across transport queues, retries, asynchronous credentials, or application future chains.

Validation

• All six new regressions fail on unmodified 46bf1c1 and pass with this change.
• SKIP_MOCK_TESTS=true ./gradlew :openai-java-core:test :openai-java-client-okhttp:test: 6,050 passed, 598 skipped.
• Core and OkHttp Kotlin lint tasks and git diff --check pass.
• Castiron budget passes at 2,492 of 3,000 lines, without changing the policy.

The generator source is not present here; the same substitution is applied consistently to the checked-in service implementations.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-10T10:04:24.258769Z	2a0e4f8	PR opened
🔒 Security Review	✅ Completed 2026-09-10T10:02:46.101427Z	2a0e4f8	PR opened

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[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 2a0e4f8b80

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[sylvesterkaczmarek]

@codex review

[sylvesterkaczmarek]

The queued-dispatcher context issue is addressed and the review thread is resolved. Current head is 0 behind main. Validation on JDK 21: AsyncRequestDispatchTest passes, RetryingHttpClientTest passes, and git diff --check is clean. Could a maintainer review the current head when convenient?