How to constantly get new JSON information with GET request from a stream? Help!!

Hello :)

I have a task to learn how to use various API's and I managed to connect and send simple GET requests (I am using this API and this is one of the examples: http://www.meetup.com/meetup_api/docs/find/events/). But I cannot figure out how can I constantly get new information from this stream: http://stream.meetup.com/2/rsvps (more about this: http://www.meetup.com/meetup_api/docs/stream/2/rsvps/#polling) If I use UnityWebRequest.Get() or WWW www = new WWW(), it just loads forever (I think because GET never stops getting new information. These methods work perfectly with simple GET requests). I probably need to use something similar like events, to get some functions called whenever new JSON information is uploaded, but I cannot figure out how. Please help!