This change reduces the default value from 100 mb to a more sane 1 mb.

This helps protect the server against denial of service attacks by
malicious clients sending huge amounts of data.

Backported from 734f9d1

The `main` entry for the `package.json` file is for defining the entry
point. The entry is currently missing the required `.js` extension,
this PR brings it back.

Backported from 17b8c2f

There was two issues with this behavior:

- v3 clients (with allowEIO3: true) were also receiving a "ping" after
a successful upgrade, which is incorrect (in v3, it's the client that
sends the "ping", and the server answers with a "pong")

- the ping timer is not reset after upgrade on the client-side, so an
upgrade which took longer than the `pingTimeout` duration could lead to
a "ping timeout" error on the client-side

I think the latter issue is present since the initial implementation.

Related: socketio/socket.io-client-swift#1309 (comment)

Backported from ff2b8ab

This value was updated from 60000 to 5000 in [1], included in
`[email protected]` (Feb 2018).

The reasoning back then:

Some users experienced long delays between disconnection on the
server-side and on the client-side. The "disconnect" event would take a
long time to fire in the browser, probably due to a timer being
delayed. Hence the change.

That being said, the current value (5s) now causes unexpected
disconnections when a big payload is sent over a slow network, because
it prevents the ping-pong packets from being exchanged between the
client and the server. This can also happen when a synchronous task
blocks the server for more than 5 seconds.

The new value (20s) thus seems like a good balance between quick
disconnection detection and tolerance to various delays.

Note: pingInterval + pingTimeout is still below the threshold of React
Native, which complains if a timer is set with a delay of more than 1
minute.

[1]: 65b1ad1

Related:

- socketio/socket.io#2770
- socketio/socket.io#2769
- socketio/socket.io#3054
- socketio/socket.io#3376

Backported from 5a7fa13

Diff: 3.5.0...3.6.0

Before this change, receiving an HTTP2 upgrade would make the server
crash:

> Error: read ECONNRESET
>    at TCP.onStreamRead (node:internal/stream_base_commons:217:20) {
>  errno: -104,
>  code: 'ECONNRESET',
>  syscall: 'read'
> }

This can be reproduced with Node.js v14.15.3, v16.18.1 and v18.12.1.

Backported from 425e833

Diff: 3.6.0...3.6.1