*/
  var typeHint: Any?
    get() = typeHintStack.lastOrNull()
    set(value) {
      typeHintStack[typeHintStack.size - 1] = value
    }

  /** Names leading to the current location in the ASN.1 document. */
  private val path = mutableListOf<String>()

  /**
   * False unless we made a recursive call to [write] at the current stack frame. The explicit box

    assertThat("Thu, 01 Jan 1970 00:00 GMT".toHttpDateOrNull()).isNull()
    // Extra spaces treated as bad.
    assertThat("Thu,  01 Jan 1970 00:00 GMT".toHttpDateOrNull()).isNull()
    // Missing leading zero treated as bad.
    assertThat("Thu, 1 Jan 1970 00:00 GMT".toHttpDateOrNull()).isNull()

    // RFC 850, obsoleted by RFC 1036 with any TZ.
    assertThat("Thursday, 01-Jan-1970 00:00:00 GMT-01:00".toHttpDateOrNull()!!.time)

    // Mixed case.
    checkPublicSuffix("COM", null)
    checkPublicSuffix("example.COM", "example.com")
    checkPublicSuffix("WwW.example.COM", "example.com")
    // Leading dot.
    checkPublicSuffix(".com", null)
    checkPublicSuffix(".example", null)
    checkPublicSuffix(".example.com", null)
    checkPublicSuffix(".example.example", null)
    // Unlisted TLD.

exchange.aero
express.aero
federation.aero
flight.aero
fuel.aero
gliding.aero
government.aero
groundhandling.aero
group.aero
hanggliding.aero
homebuilt.aero
insurance.aero
journal.aero
journalist.aero
leasing.aero
logistics.aero
magazine.aero
maintenance.aero
media.aero
microlight.aero
modelling.aero
navigation.aero
parachuting.aero
paragliding.aero
passenger-association.aero
pilot.aero
press.aero

16FE5..16FEF  ; disallowed                             # NA   <reserved-16FE5>..<reserved-16FEF>
16FF0..16FF1  ; valid                                  # 13.0 VIETNAMESE ALTERNATE READING MARK CA..VIETNAMESE ALTERNATE READING MARK NHAY
16FF2..16FFF  ; disallowed                             # NA   <reserved-16FF2>..<reserved-16FFF>