How to speedup writeFile?

I have a code to read a real folder from File Access API into lightningFS.

The repo is about 800kb, has 300 files.

The code works very slowly, because of writeFile (~1.3 sec).

I've read that indexedDB throttles `writeFile`, is that so?
How to speedup?

Here's the code, it recursively reads all dirs/files and uses `fs.promises.writeFile` to write them to lightningFS.

This `writeFile` call is the main reason for the delay, even though the data is very small.

```js run
let fs = new LightningFS('fs', {wipe: true});

let relPath = [''];

async function handle(dirHandle) {
console.time(dirHandle.name);

for await (const entry of dirHandle.values()) {
if (entry.kind === "file") {
const file = await entry.getFile();
let data = new Uint8Array(await file.arrayBuffer());
let filePath = [...relPath, file.name].join('/');
await fs.promises.writeFile(filePath, data);
}

if (entry.kind === "directory") {
const newHandle = await dirHandle.getDirectoryHandle( entry.name, { create: false } );
relPath.push(entry.name);
let dirPath = relPath.join('/');
await fs.promises.mkdir(dirPath);
await handle(newHandle);
relPath.pop();
}
}
}
```

P.S. Is there any other backend for lightningFS? I need a simple in-memory strorage.
It's quite ironic that lightningFS is so sluggish for a tiny test repo.
Maybe I'm doing something wrong?