anchor.diff:    gen_server:start_link(?MODULE, Opts, []).
   stop(Pid) ->
     gen_server:cast(Pid, stop).
  +
  +seq(Pid) ->
  +  gen_server:call(Pid, seq).
   
   ping(Pid) ->
     gen_server:call(Pid, ping).
  
positive.code: sock_send(Sock, Msg) ->
    gen_tcp:send(Sock, seto_frame:frame(eto, seto_piqi:gen_message(Msg))).
  
  replay_msg(Msg) ->
    Msg#seto_message{replay=true}.
  
  
negative.code: %% API Function Exports
  %% ------------------------------------------------------------------
  
  -export([start_link/1, stop/1, seq/1]).
  
  %% send payloads
  -export([ping/1, order/6, order_cancel/2]).
  