) {
    // No TLS extensions if the socket class is custom.
    if (matchesSocket(sslSocket)) {
      val bcSocket = sslSocket as BCSSLSocket

      val sslParameters = bcSocket.parameters

      // Enable ALPN.
      sslParameters.applicationProtocols = Platform.alpnProtocolNames(protocols).toTypedArray()

      bcSocket.parameters = sslParameters
    }
  }

  companion object {
    val factory =

      if (isAndroid) {
        findAndroidPlatform()
      } else {
        findJvmPlatform()
      }

    private fun findAndroidPlatform(): Platform {
      AndroidLog.enable()
      return Android10Platform.buildIfSupported() ?: AndroidPlatform.buildIfSupported()!!
    }

    private fun findJvmPlatform(): Platform {
      if (isConscryptPreferred) {

    the OkHttp version in custom `User-Agent` headers.

 *  Fix: Don't crash when running as a plugin in Android Studio Canary 4.1. To enable
    platform-specific TLS features OkHttp must detect whether it's running in a JVM or in Android.
    The upcoming Android Studio runs in a JVM but has classes from Android and that confused OkHttp!

    platform.assumeNotAndroid()

    // Accessing an URL protocol that was not enabled. The URL protocol mailto is not tested and
    // might not work as expected. It can be enabled by adding the --enable-url-protocols=mailto
    // option to the native-image command.
    platform.assumeNotGraalVMImage()
    val javaNetUrl = URL("mailto:******@****.***")
    assertThat(javaNetUrl.toHttpUrlOrNull()).isNull()
  }

object OkHttpDebugLogging {
  // Keep references to loggers to prevent their configuration from being GC'd.
  private val configuredLoggers = CopyOnWriteArraySet<Logger>()

  fun enableHttp2() = enable(Http2::class)

  fun enableTaskRunner() = enable(TaskRunner::class)

  fun logHandler() =
    ConsoleHandler().apply {
      level = Level.FINE
      formatter =
        object : SimpleFormatter() {

  fun size(): Int = Integer.bitCount(set)

  // TODO: honor this setting.
  fun getEnablePush(defaultValue: Boolean): Boolean {
    val bit = 1 shl ENABLE_PUSH
    return if (bit and set != 0) values[ENABLE_PUSH] == 1 else defaultValue
  }

  fun getMaxConcurrentStreams(): Int {
    val bit = 1 shl MAX_CONCURRENT_STREAMS

    sslSocket: SSLSocket,
    hostname: String?,
    protocols: List<@JvmSuppressWildcards Protocol>,
  ) {
    if (sslSocket is BCSSLSocket) {
      val sslParameters = sslSocket.parameters

      // Enable ALPN.
      val names = alpnProtocolNames(protocols)
      sslParameters.applicationProtocols = names.toTypedArray()

      sslSocket.parameters = sslParameters
    } else {

    if (headerName.equals(name(h), ignoreCase = true)) {
      val header = Buffer().writeUtf8(value(h))
      try {
        header.readChallengeHeader(result)
      } catch (e: EOFException) {
        Platform.get().log("Unable to parse challenge", Platform.WARN, e)
      }
    }
  }
  return result
}

@Throws(EOFException::class)
private fun Buffer.readChallengeHeader(result: MutableList<Challenge>) {
  var peek: String? = null

### Threads

#### Application's calling thread

The application-layer must block on writing I/O. We can't return from a write until we've pushed its bytes onto the socket. Otherwise, if the write fails we are unable to deliver its IOException to the application. We would have told the application layer that the write succeeded, but it didn't!

    sslSocket: SSLSocket,
  ): ConnectPlan {
    if (connectionSpecIndex != -1) return this
    return nextConnectionSpec(connectionSpecs, sslSocket)
      ?: throw UnknownServiceException(
        "Unable to find acceptable protocols." +
          " isFallback=$isTlsFallback," +
          " modes=$connectionSpecs," +
          " supported protocols=${sslSocket.enabledProtocols!!.contentToString()}",
      )
  }