KafkaOptions

How Wow reaches Kafka (kafka-clients only): the bootstrapServers, and properties passed to every producer and consumer as they are (security, client id, timeouts, batching, ...).

A few settings are Wow's and win over properties, since the transport's guarantees rest on them:

• the producer is idempotent with acks=all (producerConfig): an acknowledged message is on every in-sync replica, and a retry within the producer writes no duplicate;

• a consumer has no group and commits nothing (consumerConfig): the runtime assigns partitions by its leases and keeps the offsets in its checkpoint store; it resets no offset on its own (auto.offset.reset=none): a read whose offset is no longer retained is an offset gap, which the source handles by its OffsetGapPolicy; asking about a topic never creates it (allow.auto.create.topics=false), so a topic is made only by its owner, by an operator or by wow.kafka.ddl=auto, with the partitions it needs;

• keys are strings, values bytes.

pollTimeout bounds one poll of a source's read, so a cancelled read stops within it. metadataMaxAge is the consumers' metadata.max.age.ms unless properties set it: the longest before a consumer sees partitions added to a topic it reads, 30 seconds instead of Kafka's 5 minutes.

Fields may be added: Wow builds it from the host's configuration, so the constructor is internal to Wow.