bug#41531: 27.0.91; Better handle asynchronous eldoc backends

[Stefan Monnier]

>> I don't have the time or energy to work on eldoc myself, and apparently
>> neither do you, so the one who writes the code gets to take most of
>> the decisions.
> I have offered to do a rewrite multiple times now.

Feel free to do so.  But it does mean that one of you two will
be frustrated because your/his code won't be accepted.

Maybe a better option, then is to:

- do a quick version of the code for yourself.
- then compare that with Joao's version.
- then do a mix of:
  - argue to change or remove some parts of his code (those that would
    make it difficult for you to install your code on top of his)
  - keep the other changes to apply them after he installs his

WDYT?


        Stefan