(defn broadcast!
  "Broadcast a  event to all nginx worker processes. 
   This function can be used to notify all subscribers in different nginx
worker processes from the same nginx instance.
   `event has the form {:data data} or {:tag tag, :data data} 
   `data can be Long, String, byte[]. If it is long integer it must be less than 0x0100000000000000L
If it is string or bytes, it must be less than PIPE_BUF - 8, generally on Linux/Windows is 4088, 
on MacosX is 504
     `data will be truncated if its length exceeds this limitation.
   If `tag is given, `data can also be long integer which means this event is 
   very simple and only has a event id without any body or body is stored externally.
   The default tag value is 0x20 when `msg is Long otherwise the default value is 0x80.
   Here is a list of `tag values range:
   * System Event :0x00 ~ 0x1f -- Application should not use them
     * Application Event : 0x20 ~ 0xff
     * Simple  Event : 0x00 ~ 0x7f, only event id (7Byte), no message body
     * Complex Event : 0x80 ~ 0xff"
  [event])

(defn on-broadcast! 
  "Add a broadcasted event listener.
   Function f is like (fn[event] ... ) and event has the form {:tag tag, :data `bytes or long`, :offset offset :length length }
   `offset & `length are meamingless if data is a long integer."
  [f]);

(defn on-broadcast-event-decode!
  "Add a pair of tester & decoder to broadcast event decoder chain.
   Decoders will be called one by one and the current decode result will be past to the next decoder.
   Decoders should return decoded event which has the form {:tag tag, :data `any type of data`, :offset offset :length length }
   offset & `length are meamingless if data is a long integer.
   Function tester is a checker and only if it return true the decoder will be invoked."
  [tester decoder]);