[btipling]

> This is what I expect from neovim: provide me with async lint/checks.

It would have to be written using the new remote-plugin architecture I'd think. Plugins that were written for Vim would always be synchronous.

[kolme]

Not necessarily. The original patch Tarruda tried to get merged into Vim provided asynchronous commands in pure Vimscript (through a new kind of event for autocmd).

I would guess this feature is already in NeoVim.