Change the default close timeout for [Producer, AdminClient]#close
This approach has an advantage in fixing the default close timeout inconsistency between
AdminClient. However, this inconsistency was intended; The current `KafkaConsumer#close`'s default timeout, 30 seconds, was introduced in KIP-102 (0.10.2.0). To summarize, there are two differences between
Consumers don't have large requests.
Consumer#close is affected by consumer coordinator, whose close operation is affected by
By the above reasons, Consumer's default timeout was set a little bit different. So, we don't need to align the parity.
Moreover, this approach does not allow the users to configure a close timeout, and breaks backward compatibility. So rejected.