guard case let

gistfile1.txt

enum NetworkResponse {
  case response(URLResponse, Data)
  case error(Error)
}

func processRequestResponse(_ response: NetworkResponse) {
  guard 
    case let .response(urlResp, data) = response,
    let httpResp = urlResp as? HTTPURLResponse,
    200..<300 ~= httpResp.statusCode 
  else {
      print("Invalid response, can't process")
      return
  }
  print("Processing \(data.count) bytes…")
  /* … */
}