// RenewDelegationTokenRequest is a request to renew a delegation token that
// has not yet hit its max timestamp. Note that a client using a token cannot
// renew its own token.
RenewDelegationTokenRequest => key 39, max version 2, flexible v2+
  // HMAC is the HMAC of the token to be renewed.
  HMAC: bytes
  // RenewTimeMillis is how long to renew the token for. If -1, Kafka uses its
  // delegation.token.max.lifetime.ms.
  RenewTimeMillis: int64

// RenewDelegationTokenResponse is a response to a RenewDelegationTokenRequest.
RenewDelegationTokenResponse =>
  // ErrorCode is any error that caused the request to fail.
  ErrorCode: int16
  // ExpiryTimestamp is the millisecond timestamp this token will expire. The
  // token can be renewed up to MaxTimestamp, past which point, it will be
  // invalid. The Kafka default is 24h.
  ExpiryTimestamp: int64
  ThrottleMillis(1)