You can use the Write API to get the messages from Kafka and send it to a Rockset Collection. You would have to get the messages from Kafka and send it to a Rockset collection.
For the latter half of your question-> can you elaborate more? Are you trying to use the Apache Kafka and the Write API to send to 1 Rockset Collection? Are you trying to avoid using the Apache Kafka connector altogether by using the Write API or writing to S3, and then do a Rockset integration with S3?
Please, let me know more! Look forward to your response!