anchor.diff:                  url => binary(),                    % Can resolve to multiple IPs
                   opts => nkpacket:connect_opts(),    % Can include debug
                   weigth => integer(),                % Shared weight for all IPs
  -                pool => integer                     % Connections to start
  +                pool => integer(),                  % Connections to start,
  +                max_exclusive => integer()          % Default is pool
               }
           ],
           debug => boolean(),
  
positive.code: 
  do_resolve([Target|Rest], Config, Pid, Fun, Specs, Weights) ->
      Pool = maps:get(pool, Target, 1),
      {ConnList, Meta} = case Fun(Target, Config, Pid) of
          {ok, ConnList0, Meta0} ->
              {ConnList0, Meta0};
  
negative.code:                 false when Exclusive==false ->
                      % We started too much
                      ?DEBUG("selecting existing pid: ~p", [ConnId], State),
                      gen_server:reply(From, {ok, do_get_random_pid(Pids), Meta#{conn_id=>ConnId}}),
                      StopFun(Pid),
                      State;
                  false ->
  