I am trying to subscribe to an extraction event with Courier 2.6 (but the only documentation I can find is for 2.5). I have a class that inherits from ApplicationBase and I am trying to find the equivalent to the following line in the 2.5 documentation (which is obsolete in 2.6)

var engine = Umbraco.Courier.Core.ExtractionManager.Instance;
engine.Extracted += new EventHandler<ItemEventArgs>(engine_Extracted);

In version 2.6 I am looking at something like:

var engine = new Umbraco.Courier.Core.Extraction.RevisionExtraction(revision);
engine.Extracted += new EventHandler<ExtractionEventArgs>(engine_Extracted);

but I can't work out how I get a handle on the revision to pass to this method.

Any help appreciated, thanks in advance.