This reverts commit [1], which was included in `engine.io@5.1.0` and
`socket.io@4.1.0`.
The WebSocket connection was closed before all packets were written
out, so for example when calling `socket.disconnect(true)` on the
Socket.IO server (which disconnect from all namespaces and close the
connection), the client would receive only the first disconnect packet
and kept trying to reconnect to the other namespaces.
The only difference with the previous implementation (pre 5.1.0) is
that the "drain" event gets only called once at the end, and not after
each packet.
[1]: ad5306aeae
Related: https://github.com/socketio/engine.io/issues/648
This major bump creates a lot of noise, but it is necessary for
prettier to be able to parse new syntax such as:
- typed imports: `import { type xxx } from ...`
- private attributes: `class A { #b; #c() {} }`
So that clients in HTTP long-polling can decide how many packets they
have to send to stay under the maxHttpBufferSize value.
This is a backward compatible change which should not mandate a new
major revision of the protocol (we stay in v4), as we only add a field
in the JSON-encoded handshake data:
```
0{"sid":"lv_VI97HAXpY6yYWAAAC","upgrades":["websocket"],"pingInterval":25000,"pingTimeout":5000,"maxPayload":1000000}
```
Related: https://github.com/socketio/socket.io-client/issues/1531
