add sys

doc/systopics.md

@@ -0,0 +1,34 @@
+# eMQTT $SYS Topics
+
+## Version
+
+$SYS/broker/version
+
+## Uptime
+
+$SYS/broker/uptime
+
+## Recevied and Sent
+
+$SYS/broker/bytes/received
+$SYS/broker/bytes/sent
+
+$SYS/broker/packets/received
+$SYS/broker/packets/sent
+
+$SYS/broker/messages/received
+$SYS/broker/messages/sent
+$SYS/broker/messages/retained
+$SYS/broker/messages/stored
+$SYS/broker/messages/dropped
+
+## Client Presence
+
+$SYS/broker/clients/connected
+$SYS/broker/clients/disconnected
+
+$SYS/broker/clients/${clientId}/presences/online
+$SYS/broker/clients/${clientId}presences/offline
+
+
+