Knative camel producer creates CloudEvents. To have a valid CloudEvent, there's the need to have a field named `source`.
The knative camel producer sets this value by putting the "fromRouteId" value. This value is set by DefaultConsumer when creating the extended exchange.
However, when using the knative producer via ProducerTemplate, we miss this value. And the event is rejected because source is required by knative.
As a temporary fix, we could ask user to override the source value, as in this configuration example :
However, it doesn't seem right to suppose in the code this value is coming necessarly from a Camel Consumer.