bug#57434: 28.1.91; Terminal Emacs Mac OS flickering.

[Eli Zaretskii]

> From: Dmitrii Kuragin <kuragin@google.com>
> Date: Mon, 29 Aug 2022 11:24:45 -0700
> Cc: Eli Zaretskii <eliz@gnu.org>, 57434@debbugs.gnu.org
> 
> I see the behavior as a correct one (at least by design), but when we do 
> insert instead of writing the terminal
> flickers. Do we need to adjust some numbers or do we have to understand the 
> reason why we flush the
> content?

What do you mean by "flush the content"?  If this is what causes the
flickering, then please explain where does the code perform the
"flush".

More generally, we need to understand why insertion cause flickering
whereas writing to the terminal does not.