feat(runtime): add async task cancellation support

[0x676e67]

close: #461

[gemini-code-assist]

Summary of Changes

Hello @0x676e67, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the runtime's asynchronous capabilities by integrating robust task cancellation. It refactors existing async APIs to be more explicit about cancellation, introduces custom future types to bridge Python's asyncio with Rust's concurrency model, and ensures that long-running Rust operations can be gracefully interrupted from Python. This change improves responsiveness and resource management for asynchronous operations.

Highlights

• Asynchronous Task Cancellation: Introduced support for asynchronous task cancellation in the runtime, allowing Python's asyncio cancellation to propagate to Rust futures.
• New future Module: Added a new src/client/future.rs module containing SpawnWithCancel and AllowThreads futures to manage cancellation and ensure Python's Global Interpreter Lock (GIL) is released during Rust async operations.
• API Modernization: Converted all asynchronous client methods (e.g., get, post, request, websocket) and response/websocket operations (text, json, recv, send, close) to async functions, now accepting a CancelHandle for explicit cancellation management.
• Dependency Updates: Enabled the experimental-async feature for pyo3 and added the pin-project-lite crate to facilitate async Rust code with pyo3.
• Benchmark Metric Change: Updated benchmark result recording to report durations in milliseconds instead of seconds for finer granularity.

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[gemini-code-assist]

Code Review

This pull request introduces support for asynchronous task cancellation, a significant improvement for the library's async capabilities. The changes are well-implemented, converting many functions to async fn and using a new AllowThreads future wrapper with pyo3::coroutine::CancelHandle. This makes the async API more idiomatic and robust. I have a couple of suggestions for src/client/future.rs to make the cancellation handling even better by ensuring underlying Tokio tasks are aborted and by providing more specific error information upon cancellation.

[0x676e67]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces asynchronous task cancellation support, a significant and valuable feature for an async HTTP client. The changes are comprehensive, converting many methods to async fn and integrating pyo3's CancelHandle. A new AllowThreads future wrapper is added to manage cancellation and GIL release, which is a clean abstraction. The implementation is generally solid, and the related dependency updates in Cargo.toml are appropriate. I have one suggestion to enhance the robustness of the GIL handling in the new future.rs module. Overall, this is a well-executed feature addition.