Task groupのnext()はchild taskの処理が完了した順に返ってくるっぽいですね

using the group's next method to collect those results as they become ready:

 // Wait for all of the chopping to complete, collecting the veggies into // the result array in whatever order they're ready. while let choppedVeggie = try await group.next() { choppedVeggies.append(choppedVeggie) }

https://github.com/apple/swift-evolution/blob/main/proposals/0304-structured-concurrency.md#task-groups-and-child-tasks (edited)

apple/swift-evolution

This maintains proposals for changes and user-visible enhancements to the Swift Programming Language. - apple/swift-evolution