Separate report files that are still streamed into

We need to avoid uploading reports that are "still streaming". That means our code should either understand when the file is finished or (as a workaround) just never upload "fresh enough" reports (e.g. < 30 minutes old).

The way this is typically dealt with is to write to a temporary location (could be a hidden file or something with a particular filename marker) so that it's excluded from file listings for the uploader. Once it's done writing, you can mv the file into place.

So, ideally, this should be handled in the code which creates the report, not in the uploader.