Clojurians Log v2

Hi there I'm currently working with a slack appender for Timbre and it is a async appender. I was reading Timbre's code source, and it uses clojure agents to dispatch the appender function using send-off As i was reading more about clojure agents and send-off function, apparently: "send-off" uses a separate thread pool which can grow as-needed. However, when using this code:

{:enabled?   true
  :async?     true
  :min-level  :report
  :rate-limit nil
  :output-fn :inherit
  :fn
     (fn [{:keys [output_]}]
       (Thread/sleep 5000)
       (println "after sleep\n")}

Each agent only gets one thread, that's how they work. The send-off pool grows if there are multiple agents handling send-off actions.