Request originalRequest = chain.request();
      if (originalRequest.body() == null || originalRequest.header("Content-Encoding") != null) {
        return chain.proceed(originalRequest);
      }

      Request compressedRequest = originalRequest.newBuilder()
          .header("Content-Encoding", "gzip")
          .method(originalRequest.method(), gzip(originalRequest.body()))
          .build();

  //                the body from slack is a 0-byte-buffer
  @Override public synchronized void onOpen(WebSocket webSocket, Response response) {
    System.out.println("onOpen: " + response);
  }

  // TOOD(jwilson): decode incoming messages and dispatch them somewhere.
  @Override public void onMessage(WebSocket webSocket, String text) {
    System.out.println("onMessage: " + text);
  }