Why not make waitUntil's done compatible with Sendable?

[soranoba]

• I have read CONTRIBUTING and have done my best to follow them.

What did you do?

await waitUntil { done in
    let blockOperation = BlockOperation {}
    blockOperation.completionBlock = {
        // Compile-error (Swift6): Assigning non-sendable parameter 'done' to a @Sendable closure
        done()
    }
    queue.addOperation(asyncOperation)
}

What did you expect to happen?

done compatible with Sendable

What actually happened instead?

done does not compatible with Sendable

Environment

List the software versions you're using:

• Quick: 7.6.0
• Nimble: 13.3.0
• Xcode Version: 16.0 (16A242d)

Please also mention which package manager you used and its version. Delete the
other package managers in this list:

• Cocoapods: 1.15.2 (Use pod --version in Terminal)

Project that demonstrates the issue

None