Current state: Under Discussion
Discussion thread: here [Change the link from the KIP proposal email archive to your own email thread]
JIRA: here [Change the link from KAFKA-1 to your own ticket[Not present]
Kafka usually is used in high-performance and low latency event processing systems to save mission critical information. In such systems event processing latency is critical and must met very strict requirements - e.g. 1 millisecond per event. Kafka producer in general meet that requirement. It is asynchronous and doesn't wait for any network operation in caller thread. Except for metadata update. Usually metadata update is done periodically with ProducerConfig#METADATA_MAX_AGE_CONFIG interval.