(require '[clojure.core.async :as async :refer [<! >! timeout chan alt! alts! go]])
(defn fan-in [ins]
(let [c (chan)]
(go (while true
(let [[x] (alts! ins)]
(>! c x))))
c))
(defn fan-out [in cs-or-n]
(let [cs (if (number? cs-or-n)
(repeatedly cs-or-n chan)
cs-or-n)]
(go (while true
(let [x (<! in)
outs (map #(vector % x) cs)]
(alts! outs))))
cs))
(let [cout (chan)
cin (fan-in (fan-out cout (repeatedly 3 chan)))]
(go (dotimes [n 10]
(>! cout n)
(prn (<! cin))))
nil)