Monitor via Confluent Platform UI
The Kafka Monitoring UI can be found at http://<localhost>:9021/management/connect
Figure 1. Confluent Importing Metrics
They show up properly in my topic, and then are added to Neo4j via the sink.
Below you see the data that has been ingested into Neo4j. During my testing I got up to more than 2M events.
Figure 2. Confluent Platform Management
Kafka Connect Client Config Override Policy
In Apache Kafka 2.3.0 was introduced the ability for each source and sink connector to inherit their client configurations from the worker properties.
For further details see this link: https://cwiki.apache.org/confluence/display/KAFKA/KIP-458%3A+Connector+Client+Config+Override+Policy