handle leader changes in async producer
handle leader changes in async producer

wikimedia/operations-debs-python-pykafka,yungchin/pykafka,thedrow/samsa,benauthor/pykafka,thedrow/samsa,benauthor/pykafka,jofusa/pykafka,wikimedia/operations-debs-python-pykafka,wikimedia/operations-debs-python-pykafka,aeroevan/pykafka,sammerry/pykafka,aeroevan/pykafka,yungchin/pykafka,thedrow/samsa,jofusa/pykafka,sammerry/pykafka,benauthor/pykafka