service: add Serve method

Signed-off-by: Adphi <philippe.adrien.nousse@gmail.com>

service/service.go

@@ -37,6 +37,7 @@ type Service interface {
 
 	Options() Options
 	Start() error
+	Serve(lis net.Listener) error
 	Stop() error
 	Close() error
 }
@@ -267,6 +268,13 @@ func (s *service) run() error {
 	}
 }
 
+func (s *service) Serve(lis net.Listener) error {
+	s.mu.Lock()
+	s.opts.lis = lis
+	s.mu.Unlock()
+	return s.run()
+}
+
 func (s *service) Start() error {
 	return s.run()
 }