feat(guidelines): add new rule for sending durable event ids (#77)

api-guidelines/async/semantics/event-structure/rules/must-prepare-consumers-to-consume-events-idempotently.md

@@ -40,6 +40,7 @@ As these requirements impose quite a restriction on the producer, a separate [`s
 ::: references
 
 - [MAY provide `sequence` context attribute](../../../format/cloudevents/rules/may-provide-sequence-context-attribute.md)
+- [SHOULD send durable event IDs ](should-send-durable-event-ids.md)
 - [You cannot have exactly-once delivery](https://bravenewgeek.com/you-cannot-have-exactly-once-delivery/)
 - [Exactly-Once Semantics Are Possible: Here’s How Kafka Does It](https://www.confluent.io/de-de/blog/exactly-once-semantics-are-possible-heres-how-apache-kafka-does-it/)
 - [Processing guarantees in kafka](https://medium.com/@andy.bryant/processing-guarantees-in-kafka-12dd2e30be0e)

api-guidelines/async/semantics/event-structure/rules/should-send-durable-event-ids.md

@@ -0,0 +1,14 @@
+---
+id: R000058
+---
+
+# SHOULD send durable event IDs 
+
+An event is a message that contains information about something factual that occurred in the past. 
+Each event must have an ID that identifies the event. 
+The event ID should be the same for retries or when sending via multiple channels. Consumers should assume that events with an identical source and ID are duplicates.
+
+::: references
+
+- [id message attribute in cloud event spec](https://github.com/cloudevents/spec/blob/v1.0.2/cloudevents/spec.md#id)
+  :::