title: Azure UploadDirectoryAsync doesn't overwrite existing files if changed
body: <p>I am doing Directory upload using Microsoft.WindowsAzure.Storage.DataMovement library as below</p>
  
  <pre><code>     TransferManager.Configurations.ParallelOperations = 64;
  
           UploadDirectoryOptions options = new UploadDirectoryOptions()
                      {                              
                          ContentType = "image/jpeg",
                          Recursive = true,                   
  
                      };
  
  
      context.FileTransferred += FileTransferredCallback;
      context.FileFailed += FileFailedCallback;
      context.FileSkipped += FileSkippedCallback;
  
  
      await TransferManager.UploadDirectoryAsync(sourceDir, destDir, options:
   options, context: context, cancellationToken: cts.Token);
  </code></pre>
  
  <p>I recognized that if I changed the image with the same name, function is ignoring the image and returns exception as file exists. How can I replace the image if datemodified is changed? In the first place of course datemodified on my local pc and azure should be synchronized. </p>