Updated Kafka message

[jeongkyun-oh]

Proposed changes

• In order not to mix the messages from multi-producers, the message format is updated.
• Introduced version/producerId for the message
  • the version is added for backward-compatibility so that the old message production and consumption should work as normal.
  • the producerId is added to distinguish the messages with the same key, but from different data source.

Types of changes

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• Bugfix
• New feature or enhancement
• Others

Checklist

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• I have read the CONTRIBUTING GUIDELINES doc
• I have signed the CLA
• Lint and unit tests pass locally with my changes ($ make test)
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• Any dependent changes have been merged and published in downstream modules

[aidan-kwon]

LGTM

[yoomee1313]

It looks good to me

[hyochan-brown]

LGTM
I have a few questions!