import Foundation

func startDownload() {
  let url = URL(string: "https://example.com/large.zip")!
  BGSession.shared.session.downloadTask(with: url).resume()
}

func startUpload(file: URL) {
  var req = URLRequest(url: URL(string: "https://example.com/upload")!)
  req.httpMethod = "POST"
  BGSession.shared.session.uploadTask(with: req, fromFile: file).resume()
}

                    

import SwiftUI
import Foundation

struct ContentView: View {
  var body: some View {
    VStack(spacing: 12) {
      Button("Start Download") { startDownload() }
      Button("Start Upload") {
        let tmp = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent("upload.bin")
        try? Data(repeating: 0, count: 8).write(to: tmp)
        startUpload(file: tmp)
      }
    }
    .padding()
  }
}

                    

import SwiftUI

@main
struct MyApp: App {
  var body: some Scene {
    WindowGroup { ContentView() }
  }
}