aiokafka 0.4.0

Speed enhancements and Consumer rewrite

on Python PyPI

Major changes:

• Full refactor of the internals of AIOKafkaConsumer. Needed to avoid several
  race conditions in code (PR #286, fixes #258, #264 and #261)
• Rewrote Records parsing protocol to allow implementation of newer protocol
  versions later
• Added C extension for Records parsing protocol, boosting the speed of
  produce/consume routines significantly
• Added an experimental batch producer API for unique cases, where user want's
  to control batching himself (by @shargan)

Minor changes:

• Add timestamp field to produced message's metadata. This is needed to find
  LOG_APPEND_TIME configured timestamps.
• Consumer.seek() and similar API's now raise proper ValueError's on
  validation failure instead of AssertionError.

Bug fixes:

• Fix connections_max_idle_ms option, as earlier it was only applied to
  bootstrap socket. (PR #299)
• Fix consumer.stop() side effect of logging an exception
  ConsumerStoppedError (issue #263)
• Problem with Producer not able to recover from broker failure (issue #267)
• Traceback containing duplicate entries due to exception sharing (PR #247
  by @Artimi)
• Concurrent record consumption rasing InvalidStateError('Exception is not set.') (PR #249 by @aerkert)
• Don't fail GroupCoordinator._on_join_prepare() if commit_offset()
  throws exception (PR #230 by @shargan)
• Send session_timeout_ms to GroupCoordinator constructor (PR #229 by @shargan)

Big thanks to:

• @shargan for Producer speed enhancements and the batch produce API
  proposal/implementation.
• @vineet-rh and other contributors for constant feedback on Consumer
  problems, leading to the refactor mentioned above.