open fun getSelectedProtocol(sslSocket: SSLSocket): String? = null

  /** For MockWebServer. This returns the inbound SNI names. */
  @SuppressLint("NewApi")
  @IgnoreJRERequirement // This function is overridden to require API >= 24.
  open fun getHandshakeServerNames(sslSocket: SSLSocket): List<String> {
    val session = sslSocket.session as? ExtendedSSLSession ?: return listOf()

    upstreamSize: Long,
    metadataSize: Long,
  ) {
    val header =
      Buffer().apply {
        write(prefix)
        writeLong(upstreamSize)
        writeLong(metadataSize)
        require(size == FILE_HEADER_SIZE)
      }

    val fileOperator = FileOperator(file!!.channel)
    fileOperator.write(0, header, FILE_HEADER_SIZE)
  }

  @Throws(IOException::class)

  if (address[11] != 255.toByte()) return false

  return true
}

/** Encodes an IPv4 address in canonical form according to RFC 4001. */
internal fun inet4AddressToAscii(address: ByteArray): String {
  require(address.size == 4)
  return Buffer()
    .writeDecimalLong((address[0] and 0xff).toLong())
    .writeByte('.'.code)
    .writeDecimalLong((address[1] and 0xff).toLong())
    .writeByte('.'.code)

      // seconds are not supported by this syntax.
      require(year >= 1601)
      require(month != -1)
      require(dayOfMonth in 1..31)
      require(hour in 0..23)
      require(minute in 0..59)
      require(second in 0..59)

      GregorianCalendar(UTC).apply {
        isLenient = false
        set(Calendar.YEAR, year)

      apply {
        val maxAgeSeconds = maxAge.inWholeSeconds
        require(maxAgeSeconds >= 0) { "maxAge < 0: $maxAgeSeconds" }
        this.maxAgeSeconds = maxAgeSeconds.commonClampToInt()
      }

    fun maxStale(maxStale: Duration) =
      apply {
        val maxStaleSeconds = maxStale.inWholeSeconds
        require(maxStaleSeconds >= 0) { "maxStale < 0: $maxStaleSeconds" }

 *  Fix: Retain binary-compatibility in `okhttp3.internal.HttpMethod`. Naughty third party SDKs
    import this and we want to ease upgrades for their users.


## Version 4.0.0-RC2

_2019-06-21_

 *  New: Require Kotlin 1.3.40.
 *  New: Change the Kotlin API from `File.toRequestBody()` to `File.asRequestBody()` and
    `BufferedSource.toResponseBody()` to `BufferedSource.asResponseBody()`. If the returned value

      @JvmStatic
      fun create(
        headers: Headers?,
        body: RequestBody,
      ): Part {
        require(headers?.get("Content-Type") == null) { "Unexpected header: Content-Type" }
        require(headers?.get("Content-Length") == null) { "Unexpected header: Content-Length" }
        return Part(headers, body)
      }

      @JvmStatic
      fun createFormData(

    flags: Int,
  ) {
    if (type != TYPE_WINDOW_UPDATE && logger.isLoggable(FINE)) {
      logger.fine(frameLog(false, streamId, length, type, flags))
    }
    require(length <= maxFrameSize) { "FRAME_SIZE_ERROR length > $maxFrameSize: $length" }
    require(streamId and 0x80000000.toInt() == 0) { "reserved bit set: $streamId" }
    sink.writeMedium(length)
    sink.writeByte(type and 0xff)
    sink.writeByte(flags and 0xff)

  ) : SerialTask {
    override fun start() {
      taskRunner.assertThreadHoldsLock()
      require(currentTask == this)
      activeThreads++

      tasksExecutor.execute {
        taskRunner.assertThreadDoesntHoldLock()
        require(currentTask == this)
        try {
          runnable.run()
          require(currentTask == this) { "unexpected current task: $currentTask" }
        } finally {

  val millis = unit.toMillis(duration)
  require(millis <= Integer.MAX_VALUE) { "$name too large" }
  require(millis != 0L || duration <= 0L) { "$name too small" }
  return millis.toInt()
}

internal fun checkDuration(
  name: String,
  duration: Duration,
): Int {
  check(!duration.isNegative()) { "$name < 0" }
  val millis = duration.inWholeMilliseconds
  require(millis <= Integer.MAX_VALUE) { "$name too large" }