DnsResolver.FLAG_EMPTY,
        executor,
        null,
        object : DnsResolver.Callback<List<InetAddress>> {
          override fun onAnswer(
            addresses: List<InetAddress>,
            rCode: Int,
          ) {
            callback.onResponse(hostname, addresses)
          }

          override fun onError(e: DnsResolver.DnsException) {
            callback.onFailure(
              hostname,

    require(c in '\u0021'..'\u007e') {
      "Unexpected char 0x${c.charCode()} at $i in header name: $name"
    }
  }
}

internal fun headersCheckValue(
  value: String,
  name: String,
) {
  for (i in value.indices) {
    val c = value[i]
    require(c == '\t' || c in '\u0020'..'\u007e') {
      "Unexpected char 0x${c.charCode()} at $i in $name value" +