* either the field is absent or cannot be parsed as a date.
   */
  @IgnoreJRERequirement // Only programs that already have Instant will use this.
  fun getInstant(name: String): Instant? {
    return getDate(name)?.toInstant()
  }

  /** Returns the number of field values. */
  @get:JvmName("size")
  val size: Int
    get() = namesAndValues.size / 2