anchor.diff:  "[\"^ \",\"~:type\",\"~:query\",\"~:dest\",\"~:users\",\"~:data\",[\"^ \",\"~:some\",\"^4\"]]"
   ----
   
  -*postal* comes with a set of predefined messages with specified semantics but that
  -not limits the user to define own messages on top of that protocol.
  +*postal* comes with a set of predefined types of messages with specified semantics but that
  +doesn't limit the user to define their own messages on top of the protocol.
   
   
   == Common Messages
  
positive.code: ----
  
  After sending a `:query` message we should expect an `:response` message to be
  sent back or `:error` if an error is ocurred. The `:dest` property is mandatory.
  
  
  === :novelty
  
  This is a message that serves for submit data to be processed to a specified
  resource. It is analogous to the HTTP POST/PUT.
  
  This is the aspect of the `novelty` message:
  
  [source, clojure]
  ----
  
negative.code: 
  This is a generic message that represents a server response to some kind of request.
  
  This is how a `:response` message looks like:
  
  [source, clojure]
  ----
  