(require '[clojure.core.async :as async :refer [<! >! <!! >!! timeout chan alt! alts!! go]])
(defn fan-in [ins]
(let [c (chan)]
(future (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)]
(future (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)))]
(dotimes [n 10]
(>!! cout n)
(prn (<!! cin))))