create the session timer at the beginning of the run loop

session.go

@@ -472,7 +472,6 @@ func (s *session) preSetup() {
 	s.ctx, s.ctxCancel = context.WithCancel(context.Background())
 	s.handshakeCtx, s.handshakeCtxCancel = context.WithCancel(context.Background())
 
-	s.timer = utils.NewTimer()
 	now := time.Now()
 	s.lastPacketReceivedTime = now
 	s.sessionCreationTime = now
@@ -490,6 +489,8 @@ func (s *session) preSetup() {
 func (s *session) run() error {
 	defer s.ctxCancel()
 
+	s.timer = utils.NewTimer()
+
 	go s.cryptoStreamHandler.RunHandshake()
 	go func() {
 		if err := s.sendQueue.Run(); err != nil {