gistfile1.clj

(defn event [env type val]
  (let [rc (async/chan)]
    (async/<!!
     (async/go
      (async/>! (:queue @env)
                {:type type :val val :rc rc :time (:now @env)})
      (async/<! rc)
      (async/close! rc)))))

(time 
 (let [n 100000
       env (atom {:now 0 :queue (async/chan)})]
   ;; car
   (async/go
    (loop []
      ;;(println "Driving at " (:now @env))
      (event env :timeout 5)
      ;;(println "Parking at " (:now @env))
      (event env :timeout 2)
      (when (< (:now @env) n) (recur)))) 
   (async/<!!
    (async/go
     (loop []
       (let [e (<! (:queue @env))
             nt (+ (:val e) (:now @env))]
         (when (< nt n)
           (swap! env assoc :now nt)
           (async/go (async/>! (:rc e) true))
           (recur))))))))