Recursively updates files and nested directories starting from the specified directory.
A string that is the path to a directory from which the update starts.
Currently, always returns null.
The UpdateDirectory method recursively traverses all directories starting from the specified path. For each file, it calls the ZipArchive.UpdateFile method so that the archive path equals the file path without the root component. As a result, all file items in the archive which correspond to files in the file system are replaced with new items created from files. If a zip item that corresponds to the file is not found, it is created and added to the archive. All file items which do not correspond to files are left intact.
Empty directories are skipped and not created in the archive.