[foobarbaz33]

You could have an lsp server of infinite speed, but that wouldn't help one bit if the bottleneck is how the client deals with the messaging.

The specific techniques used to send, receive, and parse JSON could matter.

[hdjrudni]

Could, ya, but I'd be pretty impressed and sad if Rust didn't have really good JSON parsers/serializers by now.

[steveklabnik]

It’s had them for a very long time, pre-1.0.

[adastra22]

What do you mean? It has exceptionally good crates for that, and has for more than a decade. Is there something you feel is missing?

[socksy]

Well exactly, I'm pretty sure that's what the GP is getting at — it would be a surprise if Rust didn't have good JSON support. Which it does. So it's unlikely to be the bottleneck.