observer example added

examples/observer/__main__.py

@@ -0,0 +1,29 @@
+import voicemeeterlib
+
+
+class Observer:
+    def __init__(self, vm):
+        self.vm = vm
+
+    def on_update(self, subject):
+        print(subject)
+
+
+def main():
+    with voicemeeterlib.api(kind_id) as vm:
+        obs = Observer(vm)
+        vm.subject.add(obs)
+
+        try:
+            while True:
+                cmd = input("Press Return to exit\n")
+                if not cmd:
+                    break
+        except KeyboardInterrupt as e:
+            SystemExit(e)
+
+
+if __name__ == "__main__":
+    kind_id = "banana"
+
+    main()