At present, when a user triggers an incremental backfill for a table, Debezium backfills the whole table. But what if a user wants to backfill a subset of table's data. 

For example, let's assume there is a products table. And a user wants to backfill only the records of the products table which have product_id=X. 
Atm, the query that is executed behind the scenes, for the backfill,  is like

SELECT * FROM products .........

I'd like to extend the existing incremental backfill feature to accept a new user param, additional-condition. Using additional-condition, a user will be able to specify additional context for the db query. 

Current kafka incremental backfill signal:

{"type":"execute-snapshot", "data": {""data-collections":["some_db.products"], "type":"INCREMENTAL"}}

Proposed kafka incremental backfill signal:

{"type":"execute-snapshot", "data": {""data-collections":["some_db.products"], "type":"INCREMENTAL", "additional-condition":"product_id=X"}}

This will modify the query executed for the backfill to something like:
SELECT * FROM products WHERE product_id=X .........