We almost done upgrading to the latest Fubu and the last thing we need to do is junk the AjaxContinuation that was in FastPack and convert over to the one in FubuMVC. Part of that change involved some properties going away and being stored in an indexer on the AjaxContinuation object.
EG:
ajaxContinuation.showDialog = "foo"; (OLD)
ajaxContinuation["showDialog"] = "foo"; (NEW)
Right now I'm running into some issues with our unit tests where we're asking for missing keys. Normally it's just to check and make sure they're null. Is there a reason there isn't an onMissing => null besides it just hasn't been needed yet? If so, would it be ok to expose a HasData method that would let you check without having to handle an exception?