Well, Emacs has indeed a problem with blocking because it is single-threaded. To resolve that issue internally it also maintains an event loop being used to drive async. functions calls. But not all extensions leverage that yet. But I doubt the problem described in that reddit thread you cited is really caused by that. It sounds more likely the author of that Emacs fork experienced an issue with inter process communication. Who knows because there is no detailed context given.

I am using "lsp-mode" for Javascript, Typescript (including React) and even on a huge Perl repository and I don't find it to be too slow for me. I am running a five year old mediocre laptop using Ubuntu. But perhaps I don't have the same standards as the author of that Emacs fork.

> You can downplay all you'd like, but a non-issue does not spur a productive maintainer to fork the entire codebase to implement changes, or alternative clients (LSP-bridge) that manage out-of-process connections to servers in order to work around Elisp limitations.

Well, it's an impressive feat, for sure. But I don't know anyone actually using that person's fork. So I wonder whether that really is such a huge problem as the author implies.

And -- why do you care anyway since you seem to be happy using VSCode?