anchor.diff:  % api
   -export([register_hooks/0]).
   
  +% hooks
  +-export([client_login_hook/2]).
  +
   % pre_client_channels
   -export([client_request/4, client_response/4, client_event/3]).
   
  
positive.code: 
  register_hooks() ->
  	?debug("Registering client hooks."),
  	pre_hooks:add_hook(client_logged_in, ?MODULE, client_login_hook, undefined, []).
  
  %% -------------------------------------------------------------------
  %% pre_client_channels
  
negative.code: client_login_hook(undefined, ClientRecord) ->
  	?debug("Client ~p logged in; registering 'ping' channel.", [ClientRecord]),
  	#client_info{channel_manager = ChannelManager} = ClientRecord,
  	pre_client_channels:set_sup_channel(ChannelManager, ?CHANNEL, ?MODULE, []),
  	{ok, undefined}.
  