anchor.diff:  connection handle all required context, completly eliminating the overhead of
   creating and destroyng connectons. With that you can make multiple and repeated
   http connections without performance issues.
  +
  +
  +=== Is there any way to handle auth with sockets?
  +
  +The downside of using WebSocket (like as with EventSource) is that its api
  +does not allows append additional headers. The api is very limited for that. So
  +you have two ways to do it:
  +
  +1. Using the implicit authentication using cookies; that only works if your endpoint
  +is in the same domain (no cookies send in a cross domain request).
  +
  +2. Using a ticket based communication with single use tockens (just make a query
  +request for obtain a token and later making the subscription request passing the
  +token using and additional query parameter:
  +
  +[source, clojure]
  +----
  +(def sub (pc/subscribe :timeupdate nil {:params {:token my-token}}))
  +----
  +
  +[[postal-servers]]
  +=== Is there any server supports that protocol?
  +
  +At this moment the unique backend/server implementation for this library is
  +link:https://github.com/funcool/catacumba[catacumba]. And you can found the related
  +link:https://funcool.github.io/catacumba/latest/#postal[documentation] for the
  +backend handlers setup.
   
   
   == Developers Guide
  
positive.code: returned. It there also can be rejected with an exception object if something
  foreign to transport is happens (message serialization error as example).
  
  
  == Server Push
  
  In some curcumstances the request/response patterns is not enough and you want
  get notifications from the backend in a server-push manener or full bi-directional
  
negative.code: And you can close the socket just ending the output bus with `s/end!` function.
  
  
  == FAQ
  
  === Is it a replacement for WebSockets?
  