Native async json-rpc

[yyoncho]

For better visibility of native async jsonrpc implementation in core.

Repo: https://github.com/emacs-lsp/emacs

[zbelial]

Hi, have you considered implementing json-rpc as a module? IMO people can benefit from it more soon than the native async json-rpc.

FYI, I've implemented a LSP client for Emacs using rust, you can find it here. From my experience, implementing json-rpc as a module is valuable.