reducer that just hangs

core.clj

(ns reducerstest.core
  (:require [clojure.core.reducers :as r]
            [clojure.tools.trace :as t]
            [clojure.tools.trace :as tt]
            [taoensso.timbre :as timbre :only (trace debug info warn error fatal spy)]
            [taoensso.timbre.profiling :as profiling :only (p profile)]))


(defn maxvr
  "max value reducer (for a context where 0 is the smallest possible value"
  ([] 0)
  ([x y] (timbre/info :maxvr (str x ">" y)) (if (> x y) x y)))

(defn map-function
  ([x] (timbre/info :start x) (Thread/sleep (* 500 (rand))) (timbre/info :end x) x))

(defn testred []
  (let [rm    (t/trace (r/map map-function (vec (range 0 100))))
        max   (r/fold maxvr rm)]
    (println max)))

;; with 100 replaced by 1000 just hangs there after the output of t/trace