[minor] Make sendAfterClose() call the callback in the next tick

Author: lpinca

lib/websocket.js

@@ -1096,7 +1096,7 @@ function sendAfterClose(websocket, data, cb) {
       `WebSocket is not open: readyState ${websocket.readyState} ` +
         `(${readyStates[websocket.readyState]})`
     );
-    cb(err);
+    process.nextTick(cb, err);
   }
 }