anchor.diff:  
   start_demo(debug) ->
       demo([{debug, [trace]}]).
  -    
  -interval_ms() -> 60000.
   
   
   %% @spec (Connection, Queue, RpcHandler) -> RpcServer
  
positive.code: -export([start_demo/0, start_demo/1]).
  
  -record(state, {channel,
                  proxy_queue,
                  proxy_exchange,
                  rpc_exchange,
                  control_exchange,
                  correlation_id = make_ref(),
                  continuations = dict:new(),
                  stats}).
  
negative.code: -behaviour(gen_server).
  
  -include("amqp_client.hrl").
  -include("rmq_patterns.hrl").
  
  -export([init/1, terminate/2, code_change/3, handle_call/3,
           handle_cast/2, handle_info/2]).
  