Where to get ID for stopUpload?

So while the files uploads I want to be able to cancel the upload. The question is, where do I get that ID of the uploading file. Any tips? Pretty please?

I got id of one chunk but there are many more.
As I get, stopUpload doesn’t really stop an uploading of a file but of it’s chunk/package or whatever you call it. So the question is, where do I get all those file IDs?