DNS-SD name conflict resolution

[farshidtz]

In the current version, multiple service can register under the same name. Instead the service should detect the conflict and pick a new name.

When a DNS-SD service is advertised using Multicast DNS [RFC6762], if
   there is already another service of the same type advertising with
   the same name then automatic name conflict resolution will occur.  As
   described in the Multicast DNS specification [RFC6762], upon
   detecting a conflict, the service should:

   1.  Automatically select a new name (typically by appending or
       incrementing a digit at the end of the name),
   2.  Try advertising with the new name, and
   3.  Upon success, record the new name in persistent storage.

   This renaming behavior is very important, because it is key to
   providing user-friendly instance names in the out-of-the-box factory-
   default configuration. 

https://tools.ietf.org/html/rfc6763#appendix-D

[farshidtz]

dns-sd client on macOS automatically adds an index:

dns-sd -R "Test" _wot._tcp local 1003
Registering Service Test._wot._tcp.local port 1003
DATE: ---Fri 22 May 2020---
18:19:43.719  ...STARTING...
18:19:44.380  Got a reply for service Test._wot._tcp.local.: Name now registered and active

 dns-sd -R "Test" _wot._tcp local 1004
Registering Service Test._wot._tcp.local port 1004
DATE: ---Fri 22 May 2020---
18:19:50.696  ...STARTING...
18:19:52.736  Got a reply for service Test (2)._wot._tcp.local.: Name now registered and active