NOTE: This method is called only if you
implemented IwodWebNotify interface in your application,
property has received reference to
instance of your implementation.
This notification method if called during file upload if
property was set to True. It allows you to specify final
destination filename of the upload. This way file is streamed
directly to specified file, instead of being dumped to Request.Body,
and then extracted later on.
This event may be fired more than once per request, if client
uploads more than one file. File will be fully uploaded when new
UploadFilename is called (for the new file that is about to be
uploaded), or when
notification is called.