The RemoteSocket interface, which is returned when the client is
connected on another Socket.IO server of the cluster, was lacking the
`timeout()` method.

Syntax:

```js
const sockets = await io.fetchSockets();

for (const socket of sockets) {
  if (someCondition) {
    socket.timeout(1000).emit("some-event", (err) => {
      if (err) {
        // the client did not acknowledge the event in the given delay
      }
    });
  }
}
```

Related: https://github.com/socketio/socket.io/issues/4595