finfo::buffer(): Failed identify data 0:(null)

### Description

The following code:

```php
<?php
$data = pack('H*','fffe000000099999');
$mime_type = (new finfo(FILEINFO_MIME))->buffer($data);
```

Resulted in this output:
```
Warning: finfo::buffer(): Failed identify data 0:(null)
```

But I expected this output instead:
_Something instead of '(null)'_



### PHP Version

PHP 8.3.2

### Operating System

_No response_