Restructure consumer group polling runloop (fixes #1470 )

[vermas7988]

Restructure consumer group polling runloop (fixes #1470 )

[vermas7988]

Differs in linespace, due to fmt.

[erikvanoosten]

Please run sbt fmt.

[vermas7988]

Differs in linespace, due to fmt.

[erikvanoosten]

The idea posted in #1470 is to fetch the group metadata after a rebalance. The right place to do this is line 274. Currently, we clear the ref on that line. Instead, we want to fill the ref immediately with the value obtained by calling getConsumerGroupMetadataIfAny. Other places in Runloop can then read the ref directly and no longer need to call getConsumerGroupMetadataIfAny.

[vermas7988]

The idea posted in #1470 is to fetch the group metadata after a rebalance. The right place to do this is line 274. Currently, we clear the ref on that line. Instead, we want to fill the ref immediately with the value obtained by calling getConsumerGroupMetadataIfAny. Other places in Runloop can then read the ref directly and no longer need to call getConsumerGroupMetadataIfAny.

I raised another PR, will close this one. But probably we would need to initialise the group metadata ref before first rebalance, there is a test failing. Investigating more: #1474