Streams uses KafkaClientSupplier to get consumer/restore-consumer/producer clients. Streams also uses one more client for admin purpose namely StreamsKafkaClient that is instantiated "manually".
With the newly upcoming AdminClient from KIP-117, we can simplify (or even replace StreamsKafkaClient with the new AdminClient. We furthermore want to unify how the client in generated and extend KafkaClientSupplier with method that return this client.
NOTE: The public facing changes are summarized in a separate ticket
KAFKA-6170, and this ticket is only for the internal swap, with the accepted criterion to completely remove StreamsKafkaClient with the newly introduced KafkaAdminClient.