Cannot use blob value in saveAs from Instagram In-App Browser

a solution like:
```js
saveAs("original-file.pdf", "new-file.pdf");
```
works fine in every browser i've checked also instagram browser.

But a solution based on download a blob content does not work on Instagram In-APP (but is working on Chrome, and "regular" browsers).

```js
var url = "file.pdf";
var name = "test";
var opts = "";

var xhr = new XMLHttpRequest();
xhr.open('GET', url);
xhr.responseType = 'blob';

xhr.onload = function () {
const blob = new Blob([xhr.response], { type: 'application/pdf' });
saveAs(blob, name);
};

xhr.onerror = function () {
console.error('could not download file');
};

xhr.send();
```

i've been debugging for a couple of hours and i cant really know what is happening

Any idea is welcomed