Consumers

• Add RangePartitionAssignor (and use as default); add assignor tests (dpkp PR 550)
• Make sure all consumers are in same generation before stopping group test
• Verify node ready before sending offset fetch request from coordinator
• Improve warning when offset fetch request returns unknown topic / partition

Producers

• Warn if pending batches failed during flush
• Fix concurrency bug in RecordAccumulator.ready()
• Fix bug in SimpleBufferPool memory condition waiting / timeout
• Support batch_size = 0 in producer buffers (dpkp PR 558)
• Catch duplicate batch.done() calls [e.g., maybe_expire then a response errback]

Clients

Documentation

• Improve kafka.cluster docstrings
• Migrate load_example.py to KafkaProducer / KafkaConsumer

Internals

• Dont override system rcvbuf or sndbuf unless configured explicitly (dpkp PR 557)
• Some attributes may not exist in __del__ if we failed assertions
• Break up some circular references and close client wake pipes on __del__ (aisch PR 554)