How can I track connected clients if my system account misses a connection event?

[brettinternet]

I can track client connection changes to a NATS server with:

client.Subscribe("$SYS.ACCOUNT.*.CONNECT", func(m *nats.Msg) {
	fmt.Println("connected", string(m.Subject))
})

client.Subscribe("$SYS.ACCOUNT.*.DISCONNECT", func(m *nats.Msg) {
	fmt.Println("connected", string(m.Subject))
})

However, if my server misses an event during redeployments, I'd like to be able to query the NATS server for currently connected clients on startup in order to evaluate an "online" status for a user interface. I'm prototyping using NATS with IoT devices and want to keep track of which devices are online.

Can I query the server for connections? I know I can do this with the monitoring endpoint. But perhaps this can also be performed with the system account?

[brettinternet]

It looks like I can use $SYS.REQ.SERVER.<server ID>.CONNZ.

serverID := client.ConnectedServerId()
msg, _ = client.Request(fmt.Sprintf("$SYS.REQ.SERVER.%s.CONNZ", serverID), nil, 5*time.Second)
fmt.Println(subject, "message:", string(msg.Subject), string(msg.Data))

My two follow up questions to this are:

1. How can I paginate this request response?
2. Is the server ID in $SYS.REQ.SERVER.<server ID>.CONNZ for a single server or does it monitor the entire cluster for a multi-server setup?

[brettinternet]

I'm able to paginate with the request data matching the monitoring query params for pagination:

type paginate struct {
	Offset int `json:"offset"`
	Limit  int `json:"limit"`
}
var body = paginate{
	Offset: 0,
	Limit:  1,
}
data, _ := json.Marshal(body)
subject = fmt.Sprintf("$SYS.REQ.SERVER.%s.CONNZ", client.ConnectedServerId())
msg, _ = client.Request(subject, result, 5*time.Second)
fmt.Println(subject, "message:", string(msg.Subject), string(msg.Data))

Does anyone know if the server ID client.ConnectedServerId() or $SYS.REQ.SERVER.<server ID>.CONNZ monitoring represents metrics for the entire cluster?