Changelog

Improvements:

The producer's behaviour when Flush.Frequency is set is now more intuitive (#389).
The consumer produces much more useful logging output when leadership changes (#385).

Bug Fixes:

The OffsetCommitRequest message now correctly implements all three possible API versions (#390, #400).

Improvements:

Wrap the producer's partitioner call in a circuit-breaker so that repeatedly broken topics don't choke throughput (#373).

Bug Fixes:

Fix the producer's internal reference counting in certain unusual scenarios (#367).
Fix the consumer's internal reference counting in certain unusual scenarios (#369).
Fix a condition where the producer's internal control messages could have gotten stuck (#368).
Fix an issue where invalid partition lists would be cached when asking for metadata for a non-existant topic (#372).

Version 1.0.0 is the first tagged version, and is almost a complete rewrite. The primary differences with previous untagged versions are:

The producer has been rewritten; there is now a SyncProducer with a blocking API, and an AsyncProducer that is non-blocking.
The consumer has been rewritten to only open one connection per broker instead of one connection per partition.
The main types of Sarama are now interfaces to make depedency injection easy; mock implementations for Consumer, SyncProducer and AsyncProducer are provided in the github.com/Shopify/sarama/mocks package.
For most uses cases, it is no longer necessary to open a Client; this will be done for you.
All the configuration values have been unified in the Config struct.
Much improved test suite.