(ns my-ns.core
    (:require  [clojure.core.async :refer
                [timeout thread alt! alts! chan go-loop <! >! put! chan close!]]))

(defn takes-a-while [chan x]
  (println "starting long running query")
  (thread (Thread/sleep 5000)
          (put! chan x)))

(defn run-it []
  (let [c (chan)]
    (takes-a-while c 5)
    (go-loop []
      (let [[val chnl] (alts! [c (timeout 500)])]
        (if (= c chnl)
          (println "got value at last" val)
          (do
            (println "still waiting...")
            (recur)))))))