fix: optimizate with context (#1460)

* fix: optimizate with context

transport/http/server.go

@@ -181,12 +181,17 @@ func (s *Server) ServeHTTP(res http.ResponseWriter, req *http.Request) {
 func (s *Server) filter() mux.MiddlewareFunc {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
-			ctx, cancel := context.WithCancel(req.Context())
-			defer cancel()
+			var (
+				ctx    context.Context
+				cancel context.CancelFunc
+			)
 			if s.timeout > 0 {
-				ctx, cancel = context.WithTimeout(ctx, s.timeout)
-				defer cancel()
+				ctx, cancel = context.WithTimeout(req.Context(), s.timeout)
+			} else {
+				ctx, cancel = context.WithCancel(req.Context())
 			}
+			defer cancel()
+
 			pathTemplate := req.URL.Path
 			if route := mux.CurrentRoute(req); route != nil {
 				// /path/123 -> /path/{id}