bug#31138: Native json slower than json.el

[Eli Zaretskii]

> Cc: sebastien@chapu.is, yyoncho@gmail.com, 31138@debbugs.gnu.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Tue, 23 Apr 2019 14:52:21 +0300
> 
> I wonder if having this optimization built-in in
> decode-coding-string or thereabouts could give us performance gains
> somewhere else as well.

I thought about this.  It could make sense to have a UTF-8 specific
function to encode and decode strings.  With encodings other than
UTF-8 it becomes trickier, and probably likewise with buffer text,
where we need to take the gap into account.

What applications do we have where en/decoding strings has critical
effect on performance?

> And this particular bug report can probably be closed.

Assuming the others confirm.