Calling eldoc-message directly

[Clément Pit-Claudel]

Hi emacs-devel,

The changelog for Emacs 27.1 says "For ElDoc support, you should set 
'eldoc-documentation-function' instead of calling 'eldoc-message' directly".

At least one of my packages calls eldoc-message directly, and I'm not sure how 
to get rid of it.

In that package, I use a server process to get information about the current 
buffer.  I can use it to asynchronously retrieve documentation about 
identifiers, among other things.  This pattern seems pretty common (I think 
that's how tide, elpy, cider, and multiple other modes work).

I currently have an eldoc-documentation-function that sends an asynchronous 
query, waits for a few milliseconds in the hope to get a quick answer, and 
otherwise registers a callback that calls eldoc-message directly.  That 
callback checks that the buffer hasn't been modified and that the point hasn't 
moved, and if so calls eldoc-message.

Can someone recommend a proper implementation, not based on eldoc-message? (I 
have vague recollections of a related thread on emacs-devel, but I can't seem 
to find it)

Thanks,
Clément.