I have a bizarre problem with callback hell, despite using async-flow Let's say I have an event ::fetch-from-x that takes an argument and ::fetch-from-y that also takes an argument, plus y needs data stored by x. When processing [::fetch-from-y "bar"], I check if I have the needed data in the db and if I don't, then:

{:fx [[:async-flow
              {first-dispatch [::fetch-from-x "foo"]
               :rules [{:when :seen?
                                 :events ::fetch-from-x-success
                                 :dispatch [::fetch-y "bar"]
                                 :halt? true}]}]]}