anchor.diff:                addr   => any,
                 port   => 0};
           true ->
  -            Undefined
  +            undefined
       end;
  -default_any(_Domain, BindAddr) ->
  +default_any(_Domain, BindAddr, _Opts) ->
       BindAddr.
   
   bind_addr(_Domain, BindIP, BindPort)
  
positive.code:    maps:from_list(OpenOpts).
  
  
  default_any(Domain, undefined = Undefined) ->
      if
          Domain =:= inet;
          Domain =:= inet6 ->
  
negative.code:                       [{start_opts, StartOpts} |
                         setopts_opts(ErrRef, ListenOpts)]),
                  ok(ErrRef, call(Server, {setopts, Setopts})),
                  ok(ErrRef, call_bind(
                               Server,
                               default_any(Domain, BindAddr, ExtraOpts)
                              )),
                  Socket = val(ErrRef, call(Server, {listen, Backlog})),
                  {ok, ?MODULE_socket(Server, Socket)}
              catch
  