) {
    // 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()
  }

Debug Logging
=============

OkHttp has internal APIs to enable debug logging. It uses the `java.util.logging` API which can be
tricky to configure. As a shortcut, you can paste [OkHttpDebugLogging.kt]. Then enable debug logging
for whichever features you need:

```
OkHttpDebugLogging.enableHttp2()
OkHttpDebugLogging.enableTaskRunner()
```

### Activating on Android

```
$ adb shell setprop log.tag.okhttp.Http2 DEBUG

    if (matchesSocket(sslSocket)) {
      try {
        // Enable session tickets.
        setUseSessionTickets.invoke(sslSocket, true)

        // Assume platform support on 24+
        if (hostname != null && Build.VERSION.SDK_INT <= 23) {
          // This is SSLParameters.setServerNames() in API 24+.
          setHostname.invoke(sslSocket, hostname)
        }

        // Enable ALPN.
        setAlpnProtocols.invoke(
          sslSocket,

  ) {
    if (sslSocket is org.openjsse.javax.net.ssl.SSLSocket) {
      val sslParameters = sslSocket.sslParameters

      if (sslParameters is org.openjsse.javax.net.ssl.SSLParameters) {
        // Enable ALPN.
        val names = alpnProtocolNames(protocols)
        sslParameters.applicationProtocols = names.toTypedArray()

        sslSocket.sslParameters = sslParameters
      }
    } else {

      val value = source.readInt()

      when (id) {
        // SETTINGS_HEADER_TABLE_SIZE
        1 -> {
        }

        // SETTINGS_ENABLE_PUSH
        2 -> {
          if (value != 0 && value != 1) {
            throw IOException("PROTOCOL_ERROR SETTINGS_ENABLE_PUSH != 0 or 1")
          }
        }

        // SETTINGS_MAX_CONCURRENT_STREAMS
        3 -> id = 4 // Renumbered in draft 10.

    mutual TLS where these roles are reversed.

    These classes make it possible to enable HTTPS in MockWebServer in [just a few lines of
    code][https_server_sample].

 *  **OkHttp now supports prior knowledge cleartext HTTP/2.** Enable this by setting
    `Protocol.H2_PRIOR_KNOWLEDGE` as the lone protocol on an `OkHttpClient.Builder`. This mode

    assertThat(socket.enabledCipherSuites)
      .containsExactly(*expectedCipherSuites.toTypedArray())
  }

  @Test
  fun tls_stringCiphersAndVersions() {
    // Supporting arbitrary input strings allows users to enable suites and versions that are not
    // yet known to the library, but are supported by the platform.
    ConnectionSpec.Builder(ConnectionSpec.MODERN_TLS)
      .cipherSuites("MAGIC-CIPHER")
      .tlsVersions("TLS9k")