var args = new MutliRecipientArgs(
         EndPointURI,
         TestSerialNumber,
         TestAPIUser,
         TestAPIPsw,
         recipients,
         HTMLBody,
         EmailSubject,
         messagePassword,
         filesArgs,
         sendingMode,
         sendMessageByMyself,
         true,
         getNotify, culture, 1, 5)
      { FilesPath = files };
      
      // Attaching events
      
      fileHelper.Before_UploadChunksErrorRetry += (IEnumerable<int> chunks, string inputFile, Guid fileIdentifier) =>
      {
          /// This is the delegate associated to the event when chunks are in errors, before retry upload.
          /// <param name="chunks">Chunks list</param>
          /// <param name="inputFile">File path</param>
          /// <param name="fileIdentifier">File ID</param>
      };
      
      fileHelper.UploadFileStart_Event += (string eventFileName, long fileSize) =>
      {
          /// This event occur before the file start to be uploaded to the server.
          var fileName = eventFileName;
          var theFileSize = fileSize;
      };

      fileHelper.UploadFileEnd_Event += (string eventFileName, long fileSize) =>
      {
          /// This event occur when all the file chunks has finish
      };
     
      fileHelper.UploadFinish_Event += () =>
      {
          /// The event call when a chuck finish upload
      };

      fileHelper.UploadFinishFiles_Event += (List<UploadFiles> uploadedFiles) =>
      {
          /// This event occur when all the files upload has finish
          for (int i = 0; i < uploadedFiles.Count; i++)
          {
              UploadFiles upf = uploadedFiles[i]; // That is the model of files chunk when file are uploaded to the Secure Exchanges server
              
              string fileName = upf.RealFileName; // Real file name of the file
              
              int fileLength = upf.BytesLenght; // The file length (the size of the file). If you need the beauty filesize, you can use the GetTextSize

              string fileSHA512 = upf.SHA512; // The file SHA512
              string fileHash = upf.Hash; // The Hex SHA512 file hash

              double originalfile_totalPart = upf.TotalPart; // The total number of chunk part that file

              Guid guid = upf.CryptedHandShakeID; // That is the cryptedHandShakeID that was use to upload the file
          }

      };
      
      // Call the multicecipient method 
      MultiRecipientAnswer answer = MessageHelper.MultiRecipientMessage(args, fileHelper);
      
      var status = answer.Status; // The state could be 200, 403, ....

   ////////////////////////////// Upload Test ////////////////////////////////////

   string filePath = GlobalSettings.LargeFilePath; // This is a large file path
   string filePathBinary = GlobalSettings.smallFilePath; // This is a small binary file
   filesPath.Add(filePathBinary); // A file list (we need it later in this example to compare)
   
   // A function that uploads the file path and the binary file and generates the link
   var url = GenerateLinkForUploadedFile(filePath, filePathBinary);


   ////////////////////////////// Download Test ////////////////////////////////////

   var msg = ReadMessage(url, "", ""); // Get the message


   FileHelper down_fh = new FileHelper(); // We create a FileHelper to attach event to downloaded files
   
   // Attaching event after each file download
   down_fh.DownloadFinish_event += (DownloadedFileWithMetaData file) =>
   {               
       var filePath = file.FilePath; // The final file path downloaded
       
       var fileName = file.FileName; // The final file name downloaded       
       
       var state = file.FileState; // The file state of the downloaded file. The state could be Process, NotProcess ...       
       
       var isFileUncrypted = file.Uncrypted; // Is the file has been successfly uncrypted           
       
       bool isSuccess = file.Success; //If the file is flagged has succces                 
   };

   // Attaching event after all download finished
   down_fh.DownloadsFinish_event += (List<DownloadedFile> files) =>
   {
       var numberOfFiles = files.Count; // Get the number of files in the collection
   };
   
   //After attachement we can start the download
   down_fh.DownloadSecureFiles(msg.FilesMetaData, "./download folder");

LogsHelper.GetLog(new GetLogArgs(EndPointURI, TestSerialNumber, TestAPIUser, TestAPIPsw, messageId));

 GetEnveloppeResponse response = SecureExchangesSDK.Helpers.MessageHelper.GetEnveloppe(new
       SecureExchangesSDK.Models.Args.GetEnveloppeArgs(EndPointURI, TestSerialNumber, TestAPIUser, TestAPIPsw, "Reply", "email1;email2;", "fr-CA")
      {
        // If you get a callback API activated set it to true, if not set it to no
        ReplyToAPI = false,
        // Object that you want to retreived when you will get back the message
        CallBackParameters = "Your callback parameter, xml, json what you want"
      });