NodeJS net.Socket: `connect` vs `ready` event

I had hard time debugging a problem with my NodeJS' code today.

I have problems when I open two connections to the same unix socket (reasons though); and for unknown reasons, sometimes it works fine throughout; and sometimes I don't get back any data, but connect is fired for only one of them.

I'm still trying to debug, but I deep dived into documentation and faced another question. As NodeJS Docs (12.x LTS) states: (about net.Socket)

# Event: 'connect'
Added in: v0.1.90
Emitted when a socket connection is successfully established. See net.createConnection().

# Event: 'ready'
Added in: v9.11.0
Emitted when a socket is ready to be used. Triggered immediately after 'connect'.

(https://nodejs.org/docs/latest-v12.x/api/net.html)

I wondered if that is where I should look for error:

what does immediately mean? Does it mean synchronously? If so, is there any difference between ready and connect?
is there any point for one using ready instead of connect for doing after-connection-established/opened tasks?
what is the difference between the two?

Thanks!

Solution

This event is emitted from net for consistency across different APIs. See the original commit here: https://github.com/nodejs/node/commit/1c8149417a5dec9b2af056f306822b8a22a09706

It was created to make developers' life easier when working with fs and net code, so that they don't have to remember all the intricate details of a given stream implementation.

In practice, the Node.js socket code does this:

self.emit('connect');
self.emit('ready');