Add support for Swift 6 concurrency

[sebsto]

Expected behavior

The project must compile in Swift 6 language mode with no warnings

Actual behavior

We enforce Swift 5 language mode on AWSLambdaRuntimeCore target because of concurrency warnings / errors on

• [LambdaHandlers.swift] has two warning here and here

• Lambda+LocalServer.swift : waiting for Swift NIO to provide an Swift 6 compliant HTTP Server example
  See https://github.com/apple/swift-nio/blob/main/Sources/NIOHTTP1Server/main.swift

• LambdaRuntimeCore.swift : adding support for cancellable Task introduced a couple of concurrency warning.

Steps to reproduce

swift build -Xswiftc -strict-concurrency=complete

If possible, minimal yet complete reproducer code (or URL to code)

n/a

What version of this project (swift-aws-lambda-runtime) are you using?

main

Swift version

swift-driver version: 1.115.1 Apple Swift version 6.0.3 (swiftlang-6.0.3.1.10 clang-1600.0.30.1)
Target: arm64-apple-macosx15.0

Amazon Linux 2 docker image version

swift:amazonlinux2

[sebsto]

Currently opened PR

• Mock Server : [test] Update mock server for Swift 6 compliance #463
• Local Server : [core] Update Local Server for Swift 6 compliance #464

[sebsto]

Compiling the library in Swift 6 mode causes the compiler to crash on Linux and macOS
see swiftlang/swift#78926

[sebsto]

I think the LambdaHandlers.swift warning can be suppressed by just removing the sending keyword here

swift-aws-lambda-runtime/Sources/AWSLambdaRuntimeCore/LambdaRuntime.swift

Line 35 in 7aa746f

handler: sending Handler,

I tried and, all compiler errors / warning are gone and I can see any side effect on the examples.

I think it's safe to remove sending there. wdyt @fabianfett ?

[sebsto]

Solved by #482