case classOptionalFieldDescriptor[F, R <: Record[R], M <: MetaRecord[R]](name: String, longName: String, id: Int, annotations: Map[String, String], owner: M, getter: (R) ⇒ Option[F], setterRaw: (M.Raw, F) ⇒ Unit, unsetterRaw: (M.Raw) ⇒ Unit, manifest: Manifest[F]) extends OptionalField[F, M] with FieldDescriptor[F, R, M] with Product with Serializable