Update file README.md

demos/demo2/README.md

@@ -63,6 +63,38 @@ Security-related data can be stored in the security submodel (refer to /model/se
 
 Since permission-granting decisions are made by the opa-server (if security enabled), this data must provided (in simpler format) to it and continiously updated (if changes occur). This is handled by the S3IBServer Component utilizing the security.py::get_dict_from_security_submodel method.  
 
+### Events 
+
+Create server-side Events (S3IBServer expects events to be stored in a separate submodel with a fixed id). 
+In the following, any changes (received set-Requests) to Auftragsstatus cause an event message to be sent to topic123 (and all queues bound/subscribed to it):
+
+```
+events = model.Submodel(
+    id_="https://www.company.com/submodels/events",
+    id_short="Events"
+)
+
+event = model.BasicEventElement(
+    id_short="Auftragsstatus_Updated",
+    observed=model.ModelReference.from_referable(arbeitsauftrag.get_referable(configs.AUFTRAGSSTATUS)),
+    direction=model.Direction.OUTPUT,
+    state=model.StateOfEvent.ON,
+    message_topic="topic123"
+)
+
+events.add_referable(event)
+```
+
+On client-side events can be subscribed to and awaited using S3IBAsyncClient's awaitEvent method:
+
+```
+events_submodel_id = "https://www.company.com/submodels/events"
+events_submodel_id_encoded = base64.urlsafe_b64encode(events_submodel_id.encode()).decode()
+event: model.BasicEventElement = await client.getValue(dzwald_id, dzwald_endpoint,
+                                                        f"/aas/submodels/{events_submodel_id_encoded} \
+                                                        /submodel/submodelElements/Auftragsstatus_Updated")
+auftragsstatus_updated = await client.awaitEvent(event.message_topic)
+```