Upcoming reducible IO library for Clojure

gistfile1.clj

;; Input vector of bytes
(def vec (into (vector-of :byte)
               (repeatedly 1000000 #(rand-int 128))))

;; Output file
(def out (java.io.FileOutputStream. "out.bin"))
   
;; Classic reduction -> 3835 ms
(let [write-fn (fn [r w] (.write out w))]
  (time (reduce write-fn nil (map dec vec))))

;; Upcoming reducible IO library -> 96 ms !!!
;; batch function switches reducer to batch mode
(let [c ^java.nio.channels.FileChannel (.getChannel out)
      write-fn (fn [r w] (.write c ^java.nio.ByteBuffer w))]
  (time (reduce write-fn nil (batched (map dec vec)))))