Add a group or get the group associated with the given groupId if it already exists
Add the partition into the owned list
Add the partition into the owned list
NOTE: this is for test only
Get the group associated with the given groupId, or null if not found
The most important guarantee that this API provides is that it should never return a stale offset.
The most important guarantee that this API provides is that it should never return a stale offset. i.e., it either returns the current offset or it begins to sync the cache from the log (and returns an error code).
Asynchronously read the partition from the offsets topic and populate the cache
Store offsets by appending it to the replicated log and then inserting to cache
Remove all metadata associated with the group
When this broker becomes a follower for an offsets topic partition clear out the cache for groups that belong to that partition.
When this broker becomes a follower for an offsets topic partition clear out the cache for groups that belong to that partition.
Groups belonging to this partition of the offsets topic will be deleted from the cache.