Add watch options

registry/mdns/watcher.go

@@ -9,6 +9,7 @@ import (
 )
 
 type mdnsWatcher struct {
+	wo   registry.WatchOptions
 	ch   chan *mdns.ServiceEntry
 	exit chan struct{}
 }
@@ -26,6 +27,12 @@ func (m *mdnsWatcher) Next() (*registry.Result, error) {
 				continue
 			}
 
+			// Filter watch options
+			// wo.Service: Only keep services we care about
+			if len(m.wo.Service) > 0 && txt.Service != m.wo.Service {
+				continue
+			}
+
 			var action string
 
 			if e.TTL == 0 {