In my true love's dying breath, she whispered to me 'never commit with descriptive messages'. So I kept her promise.

types.go

@@ -23,3 +23,9 @@ type mucUnit struct {
 	// value: last user presence
 	Members sync.Map
 }
+
+type userUnit struct {
+	// key: Resource 
+	// value: last presence of this device
+	Devices sync.Map
+}