This class provides an interface to DNS Service Discovery. The
functionality of DNS-SD is described at <http://www.dns-sd.org/>.
Using the Proctocols.DNS_SD.Service class a Pike program can
announce services, for example a web site or a database server, to
computers on the local network.
When registering a service you need to provide the service name.
service type, domain and port number. You can also optionally
specify a TXT record. The contents of the TXT record varies between
different services; for example, a web server can announce a path
to a web page, and a printer spooler is able to list printer
features such as color support or two-sided printing.
The service is registered on the network for as long as the instance
of the Service class is valid.
Protocols.DNS_SD