apache
DEFAULT_AUTO_OFFSET_RESET should be "latest" according to official do…
In the official document, the default value of "kafka.consumer.auto.offset.reset" is "latest", but in the source code, "DEFAULT_AUTO_OFFSET_RESET" is "earliest".
I think the reset configuration for kafkachannel is kind of internal. Without it the channel would be able to guarantee message delivery. With "latest" it would skip a whole bunch of events when offset has to be reseted.
With "earliest" it would reset the offset when the consumer restarted or rebalanced, which will lead to message repeat consumption
Existing implementation achieves at least once message delivery. This doesn't guarantee that messages are delivered more than once (in fact it is a known downside). Exposing this configuration allows users to change the delivery characteristics of kafkachannel - if really needed - but making it default would break existing setups.
