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• We does not change the current streaming and batch style sink API. So there is no compatibility issue to the exsits existing sink implementation.
• In the long run we might need to deprecate the old streaming and batch style sink API. 
• At first we plan to migrate the StreamingFileSink to this new api.

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Rejected Alternatives

If there are alternative ways of accomplishing the same thing, what were they? The purpose of this section is to motivate why the design is the way it is and not some other way.N/A