保存

let url = "https://path-to-media"
let request = URLRequest(url: url)
let downloadTask = URLSession.shared.downloadTask(with: request) { (location, response, error) in
  guard let location = location,
        let response = response,
        let documentsPath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first else {
    return
  }
  let documentsDirectoryUrl = URL(fileURLWithPath: documentsPath)
  let documentUrl = documentsDirectoryUrl.appendingPathComponent(response.suggestedFilename)
  let _ = try? FileManager.default.moveItem(at: location, to: documentUrl)

  // documentUrl is the local URL which we just downloaded and saved to the FileManager
}.resume()