Have you looked at Pushpin [1]? (disclosure: I'm the lead dev). The goal is to be able to add it to anything, rather than requiring a certain language.
If you mean how is reconnection handled on the client side, that's up to the client. Pushpin is a server-side component with no client library. But the client could use a WebSocket library with reconnection ability, like reconnecting-websocket.
I was also been underwhelmed by options in this area, so I've been working on a Rust library called Jamsocket[1]. The idea is that all you need to do is implement a trait, overload the functions for the events you want to handle (new connection, message, etc.) and deploy it.
I still need to work on production aspects of it, but it's in a state where you can play with it for local development, so I figured I'd share it here in case any Rust developers want to tinker with it.
aw how i miss you meteor
That said, phoenix/elixir's live view accomplishes the same thing in a database agnostic way. its sync system is built on channels and scales WAY better than meteor ever could.