@Override
    protected synchronized void modifyConnectorOffsets(String connName, Map<Map<String, ?>, Map<String, ?>> offsets, Callback<Message> cb) {
        if (!modifyConnectorOffsetsChecks(connName, cb)) {
            return;
        }

        worker.modifyConnectorOffsets(connName, configState.connectorConfig(connName), offsets, cb);
    }
Single process, in-memory "herder". Useful for a standalone Kafka Connect process.
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/standalone/StandaloneHerder.java