adding IAssociative to Domina events

I'm trying to make Domina events usable as maps so that they can be used with dispatch! just like maps.  (The use-case is that I might want to receive an event, modify it slightly, and then dispatch a new event based on the old one.)  I added the IAssociative protocol in the reify of create-listener-function and assoc now works.  The next step would be making them seq-able and, eventually, printable as maps.  Any guidance on the next two steps or the overall approach?
Why is this reify here with the same -seq as o.  This is the same as calling `(seq o)`.  Maybe something like:

```clj
IPrintWithWriter
(-pr-writer [o writer opts]
  (-write writer "domina.event" (into {} (seq o))))
```