Incompatible Changes

• Delete KafkaConnection class (dpkp 769)
• Rename partition_assignment -> assignment in MemberMetadata for consistency
• Move selectors34 and socketpair to kafka.vendor (dpkp 785)
• Change api_version config to tuple; deprecate str with warning (dpkp 761)
• Rename _DEFAULT_CONFIG -> DEFAULT_CONFIG in KafkaProducer (dpkp 788)

Improvements

• Vendor six 1.10.0 to eliminate runtime dependency (dpkp 785)
• Add KafkaProducer and KafkaConsumer.metrics() with instrumentation similar to java client (dpkp 754 / 772 / 794)
• Support Sasl PLAIN authentication (larsjsol PR 779)
• Add checksum and size to RecordMetadata and ConsumerRecord (KAFKA-3196 / 770 / 594)
• Use MetadataRequest v1 for 0.10+ api_version (dpkp 762)
• Fix KafkaConsumer autocommit for 0.8 brokers (dpkp 756 / 706)
• Improve error logging (dpkp 760 / 759)
• Adapt benchmark scripts from https://github.com/mrafayaleem/kafka-jython (dpkp 754)
• Add api_version config to KafkaClient (dpkp 761)
• New Metadata method with_partitions() (dpkp 787)
• Use socket_options configuration to setsockopts(). Default TCP_NODELAY (dpkp 783)
• Expose selector type as config option (dpkp 764)
• Drain pending requests to the coordinator before initiating group rejoin (dpkp 798)
• Send combined size and payload bytes to socket to avoid potentially split packets with TCP_NODELAY (dpkp 797)

Bugfixes

• Ignore socket.error when checking for protocol out of sync prior to socket close (dpkp 792)
• Fix offset fetch when partitions are manually assigned (KAFKA-3960 / 786)
• Change pickle_method to use python3 special attributes (jpaulodit 777)
• Fix ProduceResponse v2 throttle_time_ms
• Always encode size with MessageSet (#771)
• Avoid buffer overread when compressing messageset in KafkaProducer
• Explicit format string argument indices for python 2.6 compatibility
• Simplify RecordMetadata; short circuit callbacks (#768)
• Fix autocommit when partitions assigned manually (KAFKA-3486 / #767 / #626)
• Handle metadata updates during consumer rebalance (KAFKA-3117 / #766 / #701)
• Add a consumer config option to exclude internal topics (KAFKA-2832 / #765)
• Protect writes to wakeup socket with threading lock (#763 / #709)
• Fetcher spending unnecessary time during metrics recording (KAFKA-3785)
• Always use absolute_import (dpkp)

Test / Fixtures

• Catch select errors while capturing test fixture logs
• Fix consumer group test race condition (dpkp 795)
• Retry fixture failures on a different port (dpkp 796)
• Dump fixture logs on failure

Documentation

• Fix misspelling of password (ssaamm 793)
• Document the ssl_password config option (ssaamm 780)
• Fix typo in KafkaConsumer documentation (ssaamm 775)
• Expand consumer.fetcher inline comments
• Update kafka configuration links -> 0.10.0.0 docs
• Fixup metrics_sample_window_ms docstring in consumer