bug#51523: 29.0.50; gnus-mime-view-part-externally very slow

[Eli Zaretskii]

> Date: Mon, 01 Nov 2021 21:14:14 +0000
> From: Gregory Heytings <gregory@heytings.org>
> cc: Eli Zaretskii <eliz@gnu.org>, 51523@debbugs.gnu.org, 
>     monnier@iro.umontreal.ca
> 
> I attach an improved version of file-has-changed-p.  Following Eli's 
> suggestion, it records the file size together with its timestamp.

What about expand-file-name or file-truename?  That problem still
exists in this new patch, AFAICT.