Apply Kafka Connect Single Message Transforms for topic routing and field masking

Steps

1. Add a transforms list to the connector configuration, naming each transform step (e.g., transforms=routeByRegion,maskPII).
2. For dynamic topic routing, use the RegexRouter or TimestampRouter built-in SMTs: specify transforms.routeByRegion.type=org.apache.kafka.connect.transforms.RegexRouter and supply a regex and replacement pattern that rewrite the destination topic name based on the record's original topic.
3. For field masking, use MaskField$Value with a fields list of sensitive column names; the transform replaces field values with a type-appropriate zero value (empty string, 0, null) without removing the field from the schema.
4. To drop a field entirely, use ReplaceField$Value with an exclude list instead.
5. For conditional routing based on a record field value, chain a Filter SMT (Kafka Connect 2.6+) with a predicate, or use a custom SMT class placed on the Connect worker classpath.
6. Validate the transform chain by running the connector in a test environment and inspecting output topics with a consumer before promoting.