Watchlist throws: The "path" argument must be of type string. Received null

[index.js line 60](https://github.com/lukeed/watchlist/blob/master/src/index.js#L60) is throwing:

> TypeError [ERR_INVALID_ARG_TYPE]: The "path" argument must be of type string. Received null

I added some code to debug, and found that filename = null, and type = "changed", but dir looked good.

```js
// index.js
...
async function onChange(dir, type, filename) {
if (ignores.some(x => x.test(filename))) return;

// begin my code
if (filename === null) {
throw new Error(`
filename=null
dir=${ dir}
type=${ type }
datetime=${ new Date().toString() }
`);
}
// end my code

let tmp = join(dir, filename);
if (Triggers.has(tmp)) return;
...
```

**OS:** Windows 10

**Replication:**
I have been unable to figure out replication steps. The error happens maybe once or twice per day. I believe it's correlated to using Sublime Text 4's "find all", which searches the directory that `watchlist` is watching.

Definitely not every time I do a "find all". For example, I've had `watchlist` running all this morning, and the 8th time I did "find all", `watchlist` died.

Related: https://nodejs.org/api/fs.html#filename-argument

Any thoughts on ignoring `null` file names?

Start by reading src/index.js around line 60, especially onChange and how filesystem events supply filename on Windows. Investigate the reported Sublime Text 4 “find all” activity as a possible trigger. Done means a null filename no longer crashes watchlist while normal file changes continue to trigger commands.

Written by the indexing model from the issue text.