Assigning a delegate to a background job for dropbox upload

I am using Dropbox's SDK API V1 to upload files from my iOS app. The files aren't loading in real time, but rather I push them into a queue, and they get uploaded in the background.

I can't figure out for the life of me how to take DB RestClient delegate and make it respond to a completion/failure event that happens in the background. Is that even possible?

It seems (and I am new here), that delegates are meant to respond to live events on screen. Is that even an option to assign them to anything other than a UI element/view?