anchor.diff:  
   -spec( to_packet( mqtt_message() ) -> mqtt_packet() ).
   
  --endif
  +-endif.
   
   %%----------------------------------------------------------------------------
   
  +%%
  +%% @doc message from packet
  +%%
   from_packet(#mqtt_packet{ header = #mqtt_packet_header{ type   = ?PUBLISH,
                                                           qos    = Qos, 
                                                           retain = Retain, 
  
positive.code:                    dup     = false, 
                     payload = Msg }.
  
  to_packet(#mqtt_message{ msgid   = MsgId,
                           qos     = Qos,
                           retain  = Retain,
  
negative.code: 
  -include("emqtt_packet.hrl").
  
  -export([from_packet/1, to_packet/1]).
  
  %%----------------------------------------------------------------------------
  
  