Feature Request - Live progress

[claridgicus]

It would be super cool if you could provide the facility to subscribe the progress bar to a percentage value subscription to show live progress from something like a data stream.

I am uploading a photo
I would like visiual feedback to tell me how complete the upload is based on reported progress
When I upload a file I can see the progress of the file represented as a progress bar

Additionally then I would like to customise an offset of x seconds to keep the notification around after completion. So I'd pass a subscription or a variable into the notification which would eventually resolve to 100% complete - then the notification would count down the offset and self dismiss.