* filer.replicate: commit the kafka offset after replicating, not on receipt
The partition consumer committed the offset as soon as it handed the message
to the channel, so a sink write that failed was logged and the message was
already behind the committed offset -- never redelivered, permanently missing
from the sink.
Commit in onSuccessFn instead, and hold the committed offset behind the
oldest offset that failed to replicate so a restart redelivers from there.
* filer.replicate: delete the sqs message after replicating, not on receipt
ReceiveMessage deleted the message before the replicator had a chance to run,
so a failed sink write dropped it for good. Move the delete into onSuccessFn
and leave the message in the queue otherwise, letting the visibility timeout
redeliver it.
Chris Lu