diff --git a/lib/index.js b/lib/index.js
index b74a42d..fc3d32f 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -151,14 +151,15 @@ function GracefulShutdown(server, opts) {
   // set up server/process events
   // ----------------------------------
   server.on('request', function (req, res) {
-    req.socket._isIdle = false;
+    const socket = req.socket
+    socket._isIdle = false;
     if (isShuttingDown && !res.headersSent) {
       res.setHeader('connection', 'close');
     }
 
     res.on('finish', function () {
-      req.socket._isIdle = true;
-      destroy(req.socket);
+      socket._isIdle = true;
+      destroy(socket);
     });
   });