@startuml
hide footbox
skinparam maxMessageSize 70

actor        User                            as U
participant  ProtoAsyncConsumer              as PAC
participant  "Revoke\nPartitions\nEvent"     as RPE
participant  "Partitions\nRevoked\nEvent"    as PRE
participant  "Consumer\nRebalance\nListener" as CRL
queue        "Application\nEvent\nQueue"     as AEQ
queue        "Backend\nEvent\nQueue"         as BEQ

U -> PAC: poll()
activate PAC
  PAC -> BEQ: poll()
  activate BEQ
    return

  PAC -> PAC: process background events
  ...

  PAC -> RPE: partitions()
  activate RPE
    return

  PAC -> CRL: partitionsRevoked()
  activate CRL
    return

  create PRE
  PAC -> PRE : new
  PAC -> AEQ : add()
  activate AEQ
    return

  return
@enduml

@startuml
hide empty description

[*] --> NOT_IN_GROUP
NOT_IN_GROUP ---> UNJOINED : Consumer.subscribe()

UNJOINED ---> UNJOINED : Heartbeat on retries
UNJOINED ---> STABLE : Heartbeat, epoch = 0
UNJOINED ---> FATAL

STABLE ---> RECONCILING : new assignment received\ntrigger callbacks
STABLE ---> RECONCILING : Consumer.unsubscribe()
STABLE ---> RELEASING_ASSIGNMENT : on HB fencing error, reset epoch,\ntrigger callbacks
STABLE ---> FATAL
STABLE ---> STABLE : Heartbeat

RECONCILING ---> RECONCILING : Heartbeat
RECONCILING ---> RECONCILIATION_COMPLETE : callback completed
RECONCILIATION_COMPLETE ---> STABLE : Send heartbeat w/ full assignment,\nreset interval timer to\nheartbeat.interval.ms
RECONCILIATION_COMPLETE ---> STABLE : Send heartbeat w/ full assignment,\nreset interval timer to\nheartbeat.interval.ms
RECONCILIATION_COMPLETE ---> UNJOINED : unsubscribe()

RELEASING_ASSIGNMENT ---> RELEASING_ASSIGNMENT_COMPLETE : 'onLost' callback completed
RELEASING_ASSIGNMENT_COMPLETE ---> UNJOINED : Send out-of-interval HB
RELEASING_ASSIGNMENT ---> FATAL

FATAL ---> [*]

@enduml