Export Not working behind Cloudflare with HTTP2

Hi,
The export function does not work when Clouflare is used as proxy (CDN and protection).
– The exported file is generated and a file download is being initiated in the browser
– The download fails just before to finish.
On Chrome displays “Network Error” and Firefox displays “[filename] could not be saved, because the source file could not be read.”

There are some info online about the issue:
https://community.cloudflare.com/t/file-download-from-website-failing/81700
https://community.cloudflare.com/t/downloads-are-failing-timing-out/7588
https://community.cloudflare.com/t/files-can-not-be-downloaded/5598/7

The ways to fix this are:
1) – Point to the actual file instead of creating it on the fly. Save on uploads and then remove it.
2) – Report the correct file size: I think this may not be possible the way you generate the file and the reason this is failing.
3) – Disable http2 in Cloudflare settings. Not a real option.

For 2 maybe removing the file size could work (line 212 of export.php)
I am testing it and I will let you know.