Ability to add additional files to a StreamedResponse

[OzanKurt]

I've just had a case where I needed to add an extra PDF file to the downloaded zip file along with the users documents collection.

I wasn't able to do something like ->addMedia($myCustomFilePath). I believe this feature would be very useful.

I tried getting the ZipStream and calling addMedia there but wasn't able to convert the stream to a response for some reason.