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And a boolean flag whether it is being redelivered or not (first attempt)
In Camel 1.x: The header org.apache.camel.Redelivered contains a boolean if the message is redelivered or not.
In Camel 2.0: The header CamelRedelivered contains a boolean if the message is redelivered or not, which is also defined on the Exchange.REDELIVERED.
Dynamically calculated delay from the exchange
In Camel 2.9 and 2.8.2: The header is CamelRedeliveryDelay, which is also defined on the Exchange.REDELIVERY_DELAY.
Is this header is absent, normal redelivery rules apply.
Which endpoint failed
Available as of Camel 2.1
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