anchor.diff:  
   %% API.
   -export([start_link/0]).
  --export([join_xnest/1]).
  +-export([get_xnest/1]).
   -export([get_xnest_count/0]).
   
   %% gen_server.
  
positive.code: %% Internal.
  %%------------------------------------------------------------------------------------------------
  
  % Internal functions should be here.
  
  
negative.code: start_link() ->
  	gen_server:start_link(?MODULE, [], []).
  
  %% @doc Get the xnest by name, a new one will be created if the specfied is not exists.
  -spec get_xnest(binary()) -> {ok, pid()}.
  get_xnest(XNestName) ->
  	gen_server:call(?MODULE, {get_xnest, XNestName}).
  
  %% @doc Get current xnest number.
  -spec get_xnest_count() -> integer().
  