[Pitch] Progress Reporting in Swift Concurrency

[chloe-yeo]

@bjhomer

// These are already part of an existing parent, 'overallProgress'
let existingPhoto3Progress = self.progress(forID: "photo3")
let existingPhoto4Progress = self.progress(forID: "photo4")

To clarify, in this example, would existingPhoto3Progress and existingPhoto4Progress be of type Foundation.Progress?