print a debug message when the server is started

server.go

@@ -89,6 +89,7 @@ func Listen(conn net.PacketConn, tlsConf *tls.Config, config *Config) (Listener,
 		errorChan:                 make(chan struct{}),
 	}
 	go s.serve()
+	utils.Debugf("Listening for %s connections on %s", conn.LocalAddr().Network(), conn.LocalAddr().String())
 	return s, nil
 }
 

server_test.go

@@ -94,7 +94,7 @@ var _ = Describe("Server", func() {
 	)
 
 	BeforeEach(func() {
-		conn = &mockPacketConn{}
+		conn = &mockPacketConn{addr: &net.UDPAddr{}}
 		config = &Config{Versions: protocol.SupportedVersions}
 	})