anchor.diff:  
   WebSockets are cool because they allow bi-directional comunication, but in some circumstances we only
   need something unidirectional, for notify the client about some changes or any other events. For this
  -purtpose exists link:https://developer.mozilla.org/en-US/docs/Server-sent_events[Server-Sent Events]
  +purpose exists link:https://developer.mozilla.org/en-US/docs/Server-sent_events[Server-Sent Events]
   and _catacumba_ also has support for it.
   
  -The *sse* handlers are very similar to websocket ones, with the principal difference that it does not
  -gives the ability to receive data:
  +The handlers for sse not differs a lot from websockets that we have seen in previous section. The
  +main difference is that the reception of the data is not allowed.
   
   [source, clojure]
   ----
   (defn time-notification
     "Handler that notifies each second
     the current server time to the client."
  +  {:handler-type :catacumba/sse}
     [context out]
     (go-loop []
       (when-let [_ (>! out (str (java.time.Instant/now)))]
  
positive.code: (>! out {:id "2"})
  ----
  
  NOTE: As you can observe, the _catacumba_'s sse support uses core.async channels, but if you are not
  happy with core.async and want use some thing different (such as manifold streams), you may want know
  that everything in _catacumba_ is implemented using abstractions and implement your own sse type
  of handler that uses manifold streams is very very easy.
  
  
  === Ring compatibility
  
negative.code: (defn echo-handler
    "This is my echo handler that serves as
    a websocket handler example."
    {:handler-type :catacumba/websocket}
    [{:keys [in out]}]
    (go-loop []
      (if-let [received (<! in)]
  