gistfile1.txt

                       (let [c (chan)]
                         (go
                           (let [func (fn [] (>! c "callback"))]
                             (.toDataUrl js/window img (fn [res]
                                                         (swap! items #(conj % [res name]))
                                                         (swap! zips-atom #(-> %
                                                                               (assoc-in [(:db/id item) :downloaded] (count @items))))
                                                         (func)
                                                         (do-zip))))
                           (let [res (<! c)]
                             (println res))))