// OffsetFetchRequest requests the most recent committed offsets for topic
// partitions in a group.
OffsetFetchRequest => key 9, max version 8, flexible v6+, group coordinator
  // Group is the group to fetch offsets for.
  Group: string // v0-v7
  // Topics contains topics to fetch offets for. Version 2+ allows this to be
  // null to return all topics the client is authorized to describe in the group.
  Topics: nullable-v2+[=>] // v0-v7
    // Topic is a topic to fetch offsets for.
    Topic: string
    // Partitions in a list of partitions in a group to fetch offsets for.
    Partitions: [int32]
  // Groups, introduced in v8 (Kafka 3.0), allows for fetching offsets for
  // multiple groups at a time.
  //
  // The fields here mirror the old top level fields on the request, thus they
  // are left undocumented. Refer to the top level documentation if necessary.
  Groups: [=>] // v8+
    Group: string
    Topics: nullable[=>]
      Topic: string
      Partitions: [int32]
  // RequireStable signifies whether the broker should wait on returning
  // unstable offsets, instead setting a retryable error on the relevant
  // unstable partitions (UNSTABLE_OFFSET_COMMIT). See KIP-447 for more
  // details.
  RequireStable: bool // v7+

// OffsetFetchResponse is returned from an OffsetFetchRequest.
OffsetFetchResponse =>
  ThrottleMillis(4) // v3+
  // Topics contains responses for each requested topic/partition.
  Topics: [=>] // v0-v7
    // Topic is the topic this offset fetch response corresponds to.
    Topic: string
    // Partitions contains responses for each requested partition in
    // a topic.
    Partitions: [=>]
      // Partition is the partition in a topic this array slot corresponds to.
      Partition: int32
      // Offset is the most recently committed offset for this topic partition
      // in a group.
      Offset: int64
      // LeaderEpoch is the leader epoch of the last consumed record.
      //
      // This was proposed in KIP-320 and introduced in Kafka 2.1.0 and allows
      // clients to detect log truncation. See the KIP for more details.
      LeaderEpoch: int32(-1) // v5+
      // Metadata is client provided metadata corresponding to the offset commit.
      // This can be useful for adding who made the commit, etc.
      Metadata: nullable-string
      // ErrorCode is the error for this partition response.
      //
      // GROUP_AUTHORIZATION_FAILED is returned if the client is not authorized
      // to the group.
      //
      // INVALID_GROUP_ID is returned in the requested group ID is invalid.
      //
      // COORDINATOR_NOT_AVAILABLE is returned if the coordinator is not available
      // (due to the requested broker shutting down or it has not completed startup).
      //
      // COORDINATOR_LOAD_IN_PROGRESS is returned if the group is loading.
      //
      // NOT_COORDINATOR is returned if the requested broker is not the coordinator
      // for the requested group.
      //
      // UNKNOWN_TOPIC_OR_PARTITION is returned if the requested topic or partition
      // is unknown.
      //
      // UNSTABLE_OFFSET_COMMIT is returned for v7+ if the request set RequireStable.
      // See KIP-447 for more details.
      ErrorCode: int16
  // ErrorCode is a top level error code that applies to all topic/partitions.
  // This will be any group error.
  ErrorCode: int16 // v2-v7
  // Groups is the response for all groups. Each field mirrors the fields in the
  // top level request, thus they are left undocumented. Refer to the top level
  // documentation if necessary.
  Groups: [=>] // v8+
    Group: string
    Topics: [=>]
      Topic: string
      Partitions: [=>]
        Partition: int32
        Offset: int64
        LeaderEpoch: int32(-1)
        Metadata: nullable-string
        ErrorCode: int16
    ErrorCode: int16