Begins an asynchronous request to upload the local directory (and its subdirectories) to the remote directory.
An IAsyncResult that references the asynchronous upload.
You can create a callback method that implements the AsyncCallback delegate and pass its name to the BeginUploadDirectory method. The state argument may be used to pass in data that will be passed to the callback method.
For more information please refer to the synchronous version of this method, UploadDirectory.