title: multipart form data request in alamofire in swift4?
body: <p>Hello i am new to swift4 and trying to call multipart form data request by alamofire library in swift4 language? here below is my code</p>
  
  <pre><code>Alamofire.upload(multipartFormData: { multipartFormData in
              multipartFormData.append("1422".data(using: String.Encoding.utf8)!, withName: "u_id")
              multipartFormData.append("How???".data(using: String.Encoding.utf8)!, withName: "firstname")
              multipartFormData.append("We are woking on it!!".data(using: String.Encoding.utf8)!, withName: "description")
          }, to: "URL_TOcall", encodingCompletion: { result in
              print("result  = \(result)")
              switch result {
              case .success(request: let request, streamingFromDisk: false, streamFileURL: nil):
                  //Success code
                  break
  
              case .failure:
                  print("failed api calling")
                  break
  
  
              case .success(let request, true, _):
                  //Code here
                  break
  
              case .success(let request, _, _):
                  // Code here
                  break
              }
  
  
          })
  }
  </code></pre>