watchFile never fires when vfs uses a real dir

Version

main

Platform

macOS 26.2

Subsystem

vfs

What steps will reproduce the bug?

test.js:

const vfs = require('node:vfs');
const fs = require('fs');

const v = vfs.create(new vfs.RealFSProvider('/tmp'));

let called = false;
v.watchFile('/a.txt', { interval: 50 }, () => {
  called = true;
});

fs.writeFileSync('/tmp/a.txt', 'x');

setTimeout(() => {
  console.log('called?', called);
}, 300);

$ node --experimental-vfs test.js

How often does it reproduce? Is there a required condition?

Always

What is the expected behavior? Why is that the expected behavior?

called? true

file changed, the listener should run

What do you see instead?

called? false

Additional information

No response

Start with test.js and the node:vfs entry points for RealFSProvider and watchFile, then reproduce the issue with node --experimental-vfs test.js. Trace why the listener is not invoked after /tmp/a.txt changes; done means the example reports called? true.