anchor.diff:  		      end,
   		  gen_server:reply(To, Reply)
   	  end),
  -    {noreply, gb_trees:insert(Caller, To, S)}.
  +    {noreply, maps:put(Caller, To, S)}.
   
   
   %% RPC aid functions ....
  
positive.code: 
  init([]) ->
      process_flag(trap_exit, true),
      {ok, gb_trees:empty()}.
  
  -spec handle_call(term(), term(), state()) ->
          {'noreply', state()} |
  
negative.code: 
  %%------------------------------------------------------------------------
  
  -type state() :: map().
  
  %%------------------------------------------------------------------------
  
  