Implementing custom consumer partition rebalancing with `BalanceStrategy` interface

[ratnadeepb]

Versions

Please specify real version numbers or git SHAs, not just "Latest" since that changes fairly regularly.

Sarama	Kafka	Go
1.37.2	2.7	1.19

Problem Description

I am checking to see if I can create a custom consumer rebalance strategy using the BalanceStrategy interface. Something along the lines of what stickyBalanceStrategy does. Issue #1575 makes me think it is possible. I understand I can simply implement something to test. But I am fairly new to Kafka and I am wondering how this maps to the AbstractPartitionAssignor. Plus an explanation of the process would be really helpful!