title: Alamofire not generating network lost/timeout error in multipart upload
body: <pre><code>    let configuration = URLSessionConfiguration.default
      configuration.timeoutIntervalForRequest = 15.0
      configuration.timeoutIntervalForResource = 15.0
      self.alamofireManager = Alamofire.SessionManager(configuration: configuration)
  
  
  self.alamofireManager.upload(multipartFormData: { (multipartFormData) in
          multipartFormData.append(UIImageJPEGRepresentation(newImage, 1)!, withName: "file", fileName: "image.jpeg", mimeType: "image/jpeg")
          if let parameters = params{
              for (key, value) in parameters {
                  multipartFormData.append(value.data(using: String.Encoding.utf8.rawValue)!, withName: key)
              }
          }
      }, to:apiURL, method: .post, headers: authHeader)
      { (result) in
          switch result {
          case .success(let upload, _, _):
              upload.uploadProgress(closure: { (progress) in
                  DDLogInfo("Image Upload Progress : \(progress)")
              })
              upload.responseJSON { response in
                  //print response.result
              }
              break
          case .failure(let error):
              if error._code == NSURLErrorTimedOut || error._code == NSURLErrorNetworkConnectionLost {
                  print("Time Out/Connection Lost Error")
              }
              DDLogInfo("Error :\(error.localizedDescription)")
              break
          }
      }
  </code></pre>
  
  <p>Here I am utilising the default session behaviour but still not getting any error for either timeout OR network connection lost. </p>
  
  <p>I am disconnection the internet connection after I start request but no error. </p>