// or duplicate fields. Valid values are:
  // - Ignore: This will ignore any unknown fields that are silently
  // dropped from the object, and will ignore all but the last duplicate
  // field that the decoder encounters. This is the default behavior
  // prior to v1.23.
  // - Warn: This will send a warning via the standard warning response
  // header for each unknown field that is dropped from the object, and