http-kit Clojure and Gloss - Insufficient bytes to decode frame

Question

I am using HTTP-KIT for write a simple server and client HTTP. And now I want to send some data encoded using gloss.

My gloss code is something like this:

(gcore/defcodec sized-string (gcore/finite-frame :uint16-be
                                     (gcore/string :utf-8)))

(gcore/defcodec ordered-map-codec 
          (gcore/ordered-map :msg sized-string
                             :type sized-string))

This code works well:

(def data {:msg "Hello World", :type "alert"})

(def encoded
  (gio/encode ordered-map-codec data))

(gio/decode ordered-map-codec encoded)

In my server/client HTTP code, I have:

For the server:

(defonce server (atom nil))

(defn handler [request]
  (println (gio/decode ordered-map-codec (get request :body ))))

(defn -main
  []
  (reset! server (run-server handler  {:port 8080})))

And for the client:

(def options {:timeout 200
              :body (gio/encode ordered-map-codec data)})

(http/post "http://localhost:8080" options
          (fn [{:keys [status headers body error]}] 
            (if error
              (println "Failed, exception is " error)
              (println "Async HTTP GET: " status))))

Then when I try use the client to send some data:

Sat Apr 18 11:24:24 BRT 2015 [worker-3] ERROR - GET /
java.lang.Exception: Insufficient bytes to decode frame.
    at gloss.io$decode.invoke(io.clj:85)
    at gloss.io$decode.invoke(io.clj:79)
    at tapahtuma_server.server$handler.invoke(server.clj:35)
    at org.httpkit.server.HttpHandler.run(RingHandler.java:91)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Async HTTP GET:  500

Thanks for any help here