An example of using (NS)Progress to show a progress bar in Finder

Download Progress Example.swift

import Cocoa

let path = "/Users/You/Pick/Any/Random/File/On/Your/System.txt"
let destination = URL(fileURLWithPath: path)

let progress: Progress = {
	let p = Progress(parent: nil, userInfo: [
		.fileOperationKindKey: Progress.FileOperationKind.downloading,
		.fileURLKey: destination,
	])
	p.isCancellable = true
	p.isPausable = false
	p.kind = .file
	p.totalUnitCount = 10
	p.publish()
	return p
}()


// Simulate downloading a file.
let timer = Timer.scheduledTimer(withTimeInterval: 0.25, repeats: true) { _ in
	progress.completedUnitCount += 1
	print("\(progress.completedUnitCount) / \(progress.totalUnitCount)")
	
	if progress.completedUnitCount == progress.totalUnitCount {
		Darwin.exit(0)
	}
}

RunLoop.current.run()

Disregard this, look at the fork at https://gist.github.com/amomchilov/7a977b9f99e898f0ff5d8e500c213aef