add support for observers.

init/end pooler on login, logout

examples/observer/observer.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/onyx-and-iris/voicemeeter-api-go/voicemeeter"
+)
+
+type observer struct{}
+
+func (o observer) OnUpdate(subject string) {
+	fmt.Println(subject)
+}
+
+func main() {
+	vmRem := voicemeeter.GetRemote("banana")
+	vmRem.Login()
+
+	o := observer{}
+	vmRem.Pooler.Publisher.Register(o)
+
+	time.Sleep(10 * time.Second)
+
+	vmRem.Logout()
+}