experiment with closing and putting in core.async

async-test.clj

(require '[clojure.core.async :refer [>! <! chan go timeout]])

(defn test-closers
  [buffer delay]
  (let [ch (chan buffer)]
    (go (dotimes [n buffer]
          (>! ch :buffer))
        (>! ch 1)
        (println 1)
        (>! ch 2)
        (println :done))
    (go (<! ch)
        (when delay
          (<! (timeout delay))
          (println "waited" delay))
        (close! ch)))
   nil)