AsyncThrowingStream.init(unfolding:) has no onCancel parameter

[ole]

Description

There's a discrepancy in the AsyncStream APIs:

• AsyncStream has an init(unfolding:onCancel:) initializer
  • The onCancel parameter is optional because it has a default argument = nil.
• AsyncThrowingStream only has init(unfolding:) without the onCancel parameter.

The proposal SE-0314: AsyncStream and AsyncThrowingStream proposes the init(unfolding:onCancel:) variant for both stream types, so not having it on AsyncThrowingStream looks like an oversight.

Forum discussion: https://forums.swift.org/t/asyncthrowingstream-init-unfolding-has-no-oncancel-parameter/76386

Reproduction

n/a

Expected behavior

n/a

Environment

Swift 6.0. I checked the API docs at https://developer.apple.com/documentation/swift/asyncthrowingstream/ on 2024-12-05.

Additional information

No response

[jamieQ]

related issue regarding API inconsistencies b/w the two types: #76547