val typeSubtype: MatchResult =
    TYPE_SUBTYPE.matchAtPolyfill(this, 0)
      ?: throw IllegalArgumentException("No subtype found for: \"$this\"")
  val type = typeSubtype.groupValues[1].lowercase()
  val subtype = typeSubtype.groupValues[2].lowercase()

  val parameterNamesAndValues = mutableListOf<String>()
  var s = typeSubtype.range.last + 1
  while (s < length) {
    val parameter = PARAMETER.matchAtPolyfill(this, s)

    }
  }

  /**
   * This is like [toLowerCase] except that it does nothing if this contains any non-ASCII
   * characters. We want to avoid lower casing special chars like U+212A (Kelvin symbol) because
   * they can return ASCII characters that match real hostnames.
   */
  private fun String.asciiToLowercase(): String {
    return when {
      isAscii() -> lowercase(Locale.US) // This is an ASCII string.
      else -> this

  @get:JvmName("scheme") val scheme: String,
  authParams: Map<String?, String>,
) {
  /**
   * Returns the auth params, including [realm] and [charset] if present, but as
   * strings. The map's keys are lowercase and should be treated case-insensitively.
   */
  @get:JvmName("authParams")
  val authParams: Map<String?, String>

  /** Returns the protection space. */
  @get:JvmName("realm")
  val realm: String?

      }
      result.add(Header(TARGET_SCHEME, request.url.scheme))

      for (i in 0 until headers.size) {
        // header names must be lowercase.
        val name = headers.name(i).lowercase(Locale.US)
        if (name !in HTTP_2_SKIPPED_REQUEST_HEADERS ||
          name == TE && headers.value(i) == "trailers"
        ) {
          result.add(Header(name, headers.value(i)))

  @JvmField val name: ByteString,
  /** Value in UTF-8 encoding. */
  @JvmField val value: ByteString,
) {
  @JvmField val hpackSize = 32 + name.size + value.size

  // TODO: search for toLowerCase and consider moving logic here.
  constructor(name: String, value: String) : this(name.encodeUtf8(), value.encodeUtf8())

  constructor(name: ByteString, value: String) : this(name, value.encodeUtf8())