bug#38807: [Feature request]: Support lisp workers like web workers.

[Eli Zaretskii]

> From: Michael Albinus <michael.albinus@gmx.de>
> Cc: HaiJun Zhang <netjune@outlook.com>,  38807@debbugs.gnu.org
> Date: Mon, 30 Dec 2019 19:31:26 +0100
> 
> The point seems to be that there is a dedicated UI thread. That we don't
> have (yet) in Emacs, and I like this idea.

We do have that on MS-Windows.  Except that you'll be surprised how
much of "UI" in Emacs cannot be done in a separate thread, mainly
because the Lisp machine is under such complete control of what the UI
does, and you cannot run several instances of the Lisp machine
simultaneously and asynchronously.