The Kafka integration publishes events to a Kafka topic, using a configurable event key. Kafka uses the key for distributing messages over partitions. You can use this to ensure some subset of messages end up in the same partition, so they can be consumed in-order. And Kafka can use the key for data retention decisions. A header "event" with the event type is included in each message. There is no need to parse it from the key.
The GCP Pub/Sub integration exposes all events as documented by Event types.
Azure Event Hub
You can configure the Kafka integration with an Azure Event Hub using the following configuration example:
[application_server.integration.kafka] # Fill in the name of your Event Hubs Namespace brokers=["<EVENT HUBS NAMESPACE>.servicebus.windows.net:9093"] # Fill in the name of your Event Hub topic="<EVENT HUB>" # TLS must be set to true tls=true # Leave this as-is username="$ConnectionString" # SAS Policy connection-string for the Event Hub password="Endpoint=sb://.."