SyncProducer publishes Kafka messages, blocking until they have been acknowledged. It routes messages to the correct broker, refreshing metadata as appropriate, and parses responses for errors. You must call Close() on a producer to avoid leaks, it may not be garbage-collected automatically when it passes out of scope.

The SyncProducer comes with two caveats: it will generally be less efficient than the AsyncProducer, and the actual durability guarantee provided when a message is acknowledged depend on the configured value of `Producer.RequiredAcks`. There are configurations where a message acknowledged by the SyncProducer can still sometimes be lost.