ConsumerGroupJoinStateInit join or rejoin, possibly with an existing assignment.

ConsumerGroupJoinStateSteady means synchronized and assigned may be an empty assignment.

ConsumerGroupJoinStateWaitAssignCall waiting for application to call *_assign().

ConsumerGroupJoinStateWaitIncrementalUnassignToComplete means that the coordinator is up and manager is assigned.

ConsumerGroupJoinStateWaitJoin JoinGroupRequest sent, awaiting response.

ConsumerGroupJoinStateWaitMetadata MetadataRequest sent, awaiting response.

ConsumerGroupJoinStateWaitSync SyncGroupRequest sent, awaiting response.

ConsumerGroupJoinStateWaitUnassignCall waiting for application to call *_unassign().

ConsumerGroupJoinStateWaitUnassignToComplete means that the coordinator is up and manager is assigned.

ConsumerGroupStateInit means the consumer group is initialization state.

ConsumerGroupStateQueryCoordinator means the consumer group is querying for group coordinator.

ConsumerGroupStateTerminated means the Consumer Group has been stopped.

ConsumerGroupStateUp means that the coordinator is up and manager is assigned.

ConsumerGroupStateWaitBroker means that the client is waiting ack from assigned consumer group manager broker thread.

ConsumerGroupStateWaitBrokerTransport means that the client is waiting for manager broker thread to connect to broker.

ConsumerGroupStateWaitCoordinator means that the client is awaiting response for outstanding query.

https://github.com/confluentinc/librdkafka/blob/v2.4.0/STATISTICS.md.

WindowStats stores rolling window statistics.