bug#41531: 27.0.91; Better handle asynchronous eldoc backends

[Dmitry Gutov]

On 26.05.2020 05:38, Stefan Monnier wrote:
> > Here's a modified approach that doesn't use a global var and should make it
> > easier to transition to using futures.
>
> I think at this stage, we should either start using futures or we should
> forget about ever using them.

We should certainly do it before Emacs 28 is released (so we won't have 
to support whatever ad-hoc option is currently being proposed).

I just don't have the time to work on futures right now. If this bug can 
wait until this weekend, at least, we can reconvene after.