(def nashorn (.getEngineByName (ScriptEngineManager.) "nashorn"))
(def pool (Executors/newFixedThreadPool 4))

(def tasks (for [i (range 10)] #(my-fun %)))
(def futures (.invokeAll pool tasks))
(for [ftr futures]
  (.get ftr))

;; There's only one nashorn engine that gets shared across the 4 threads, right?
;; What does that mean for how the work is distributed if each invocation of `my-fun` tries to execute some javascript