Using notifications or listeners with protocols and delegates (VIPER architecture)

I am creating a chat application and I have a listener set up that listens for new messages broadcasted by users. The listener starts in applicationDidBecomeActive. Normally in Viper, UI action happens in the View, the Presenter gets notified and calls an Interactor function which does some sort of network/local logic and passes it back to the Presenter which then updates the View.
How does my listener fit into all that?
How is my View notified whenever a new message is received?