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

test.js と RealFSProvider および watchFile の node:vfs エントリポイントから始め、node --experimental-vfs test.js で問題を再現します。/tmp/a.txt の変更後に listener が呼び出されない理由を追跡します; 完了条件は、例が called? true を報告することです。