// OffsetForLeaderEpochRequest requests log end offsets for partitions.
//
// Version 2, proposed in KIP-320 and introduced in Kafka 2.1.0, can be used by
// consumers to perform more accurate offset resetting in the case of data loss.
//
// In support of version 2, this requires DESCRIBE on TOPIC.
OffsetForLeaderEpochRequest => key 23, max version 4, flexible v4+
  // ReplicaID, added in support of KIP-392, is the broker ID of the follower,
  // or -1 if this request is from a consumer.
  ReplicaID: int32(-2) // v3+
  // Topics are topics to fetch leader epoch offsets for.
  Topics: [=>]
    // Topic is the name of a topic.
    Topic: string
    // Partitions are partitions within a topic to fetch leader epoch offsets for.
    Partitions: [=>]
      // Partition is the number of a partition.
      Partition: int32
      // CurrentLeaderEpoch, proposed in KIP-320 and introduced in Kafka 2.1.0,
      // allows brokers to check if the client is fenced (has an out of date
      // leader) or if the client is ahead of the broker.
      //
      // The initial leader epoch can be determined from a MetadataResponse.
      CurrentLeaderEpoch: int32(-1) // v2+
      // LeaderEpoch is the epoch to fetch the end offset for.
      LeaderEpoch: int32

// OffsetForLeaderEpochResponse is returned from an OffsetForLeaderEpochRequest.
OffsetForLeaderEpochResponse =>
  ThrottleMillis // v2+
  // Topics are responses to topics in the request.
  Topics: [=>]
    // Topic is the topic this response corresponds to.
    Topic: string
    // Partitions are responses to partitions in a topic in the request.
    Partitions: [=>]
      // ErrorCode is the error code returned on request failure.
      //
      // TOPIC_AUTHORIZATION_FAILED is returned if the client does not have
      // the necessary permissions to issue this request.
      //
      // KAFKA_STORAGE_ERROR is returned if the partition is offline.
      //
      // NOT_LEADER_FOR_PARTITION is returned if the broker knows of the partition
      // but does not own it.
      //
      // UNKNOWN_TOPIC_OR_PARTITION is returned if the broker does not know of the
      // partition.
      //
      // FENCED_LEADER_EPOCH is returned if the client is using a current leader epoch
      // older than the actual leader epoch.
      //
      // UNKNOWN_LEADER_EPOCH if returned if the client is using a current leader epoch
      // that the actual leader does not know of. This could occur when the client
      // has newer metadata than the broker when the broker just became the leader for
      // a replica.
      ErrorCode: int16
      // Partition is the partition this response is for.
      Partition: int32
      // LeaderEpoch is similar to the requested leader epoch, but pairs with the
      // next field. If the requested leader epoch is unknown, this is -1. If the
      // requested epoch had no records produced during the requested epoch, this
      // is the first prior epoch that had records.
      LeaderEpoch: int32(-1) // v1+
      // EndOffset is either (1) just past the last recorded offset in the
      // current partition if the broker leader has the same epoch as the
      // leader epoch in the request, or (2) the beginning offset of the next
      // epoch if the leader is past the requested epoch. The second scenario
      // can be seen as equivalent to the first: the beginning offset of the
      // next epoch is just past the final offset of the prior epoch.
      //
      // (2) allows consumers to detect data loss: if the consumer consumed
      // past the end offset that is returned, then the consumer should reset
      // to the returned offset and the consumer knows everything past the end
      // offset was lost.
      //
      // With the prior field, consumers know that at this offset, the broker
      // either has no more records (consumer is caught up), or the broker
      // transitioned to a new epoch.
      EndOffset: int64(-1)