How to give a file on the fly?

Question

PHP

The function generates an xml file for subsequent return to the user.
It looks like this:

<?php
header("Content-Type: text/xml");
header("Content-disposition: attachment; filename=myFile.xml");

echo get_xml();
exit;

function get_xml()
{
    $xml = '';
    $xml .= 'bla-bla-bla';

    return $xml;
}

I get an error in the browser

Unable to connect to site.
The page may be temporarily unavailable or moved to a new address.
ERR_INVALID_RESPONSE

There are no errors in the XML content generation function, if you display it on the screen, then everything works.
How to fix?