Well it is not supported. Please note a user could upload 1000 files in 1 day; it is hard to tell if the files are all uploaded at once or not since HTTP is a "connection-less" connection, i.e. after each request is handled, it is automatically disconnected.

So a user can upload 1 file each time for 1000 times, which is the same as you upload 1000 files at once. If we send notification emails, that would be a huge number of emails.