title: Alamofire, uploading MultipartFormData with struct in parameters
body: <p>how can I add struct in parameters when uploading MultipartFormData:</p>
  
  <pre><code>let parameters = [
  "parameter1": "test1",
  "parameter2": "test2"]
  
  Alamofire.upload(multipartFormData: { multipartFormData in
          for (key, value) in parameters {
              multipartFormData.append(value.data(using: String.Encoding.utf8)!, withName: key)
          }
          multipartFormData.append(structObject, withName: "user")
  
        if let imageData = UIImageJPEGRepresentation(image, 1) {
        multipartFormData.appendBodyPart(data: imageData, name: "file", fileName: "file.png",      mimeType: "image/png")
      }
      }, to: url, encodingCompletion: { encodingResult in
          switch encodingResult {
          case .success(let upload, _, _):
              upload.responseJSON { response in
                  if let value = response.result.value as AnyObject?{
                      let json = JSON(value)
                  } else {
  
                  }                    
              }
          case .failure(let encodingError):
              print(encodingError)
  
          }
      }
      )
  </code></pre>
  
  <p>I can extra parameters without any problem, but I can't add an object to parameters array</p>
  
  <p>thank you</p>