Add support for AsyncHTTPClient

[mattt]

Related to huggingface/AnyLanguageModel#127 (comment)

This PR takes a similar approach as mattt/Replay#10

[Copilot]

Pull request overview

This PR adds optional AsyncHTTPClient support to EventSource through Swift package traits (Swift 6.1+). The implementation provides an automatic fallback mechanism on Linux where EventSource can switch from URLSession to AsyncHTTPClient if URLSession encounters retryable errors, while maintaining backward compatibility through the Package@swift-6.0.swift file.

Changes:

• Adds AsyncHTTPClient as an optional dependency via package traits
• Implements fallback mechanism from URLSession to AsyncHTTPClient on Linux for retryable errors
• Adds test coverage for fallback policy logic
• Updates CI to test both default and AsyncHTTPClient configurations

Reviewed changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
Package.swift	Updates swift-tools-version to 6.1, adds AsyncHTTPClient trait and conditional dependency
Package@swift-6.0.swift	Provides backward compatibility for Swift 6.0 without trait support
Sources/EventSource/EventSource+AsyncHTTPClient.swift	Implements AsyncHTTPClient backend, streaming protocol, and fallback policy
Sources/EventSource/EventSource.swift	Refactors connection logic to support fallback mechanism and extracts reusable methods
Tests/EventSourceTests/AsyncHTTPClientTraitTests.swift	Adds tests for fallback policy and protocol conformance
README.md	Documents AsyncHTTPClient trait usage and limitations
.github/workflows/ci.yml	Adds AsyncHTTPClient variant testing to CI pipeline
Package.resolved	Adds AsyncHTTPClient and its transitive dependencies

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 8 changed files in this pull request and generated 3 comments.

Comments suppressed due to low confidence (1)

Package.swift:45

• The testTarget "EventSourceTests" should also conditionally depend on AsyncHTTPClient when the trait is enabled. The tests in AsyncHTTPClientTraitTests.swift import and use AsyncHTTPClient, NIOCore, NIOHTTP1, and NIOPosix, but these dependencies are not declared in the test target.

Add the AsyncHTTPClient dependency to the testTarget with the same trait condition to ensure the tests can compile when the trait is enabled.

        .testTarget(
            name: "EventSourceTests",
            dependencies: ["EventSource"]
        ),

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 8 changed files in this pull request and generated 1 comment.

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