||Kafka client based on librdkafka
Arnaud Le Blanc (lead)
||This extension is a librdkafka binding providing a working client for Kafka
BREAKING CHANGE: Since version 4.0, the client no longer polls for network
events at shutdown (during object destructor). This behaviour didn't give
enough control to the user in case of server issue, and could cause the script
to hang while terminating.
Starting from 4.0, programs MUST call flush() before shutting down, otherwise
some messages and callbacks may be lost.
* Fix partition 0 exposed as NULL in Message (#327 reverts #321, @arnaud-lb @nick-zh)
* Fix memory leak in consume() when messages have headers (#323, @nick-zh)