}

  /**
   * True if ALPN is used on incoming HTTPS connections to negotiate a protocol like HTTP/1.1 or
   * HTTP/2. This is true by default; set to false to disable negotiation and restrict connections
   * to HTTP/1.1.
   */
  var protocolNegotiationEnabled: Boolean = true

  /**
   * The protocols supported by ALPN on incoming HTTPS connections in order of preference. The list

      certificatePinner.check(address.url.host) {
        handshake.peerCertificates.map { it as X509Certificate }
      }

      // Success! Save the handshake and the ALPN protocol.
      val maybeProtocol =
        if (connectionSpec.supportsTlsExtensions) {
          Platform.get().getSelectedProtocol(sslSocket)
        } else {
          null
        }
      socket = sslSocket

_2022-06-12_

 *  Upgrade: [Kotlin 1.6.20][kotlin_1_6_20].
 *  Upgrade: [Okio 3.0.0][okio_3_0_0].
 *  Fix: Recover gracefully when Android's `NativeCrypto` crashes with `"ssl == null"`. This occurs
    when OkHttp retrieves ALPN state on a closed connection.


## Version 4.9.3

_2021-11-21_

 *  Fix: Don't fail HTTP/2 responses if they complete before a `RST_STREAM` is sent.


## Version 4.9.2

_2021-09-30_

     *
     * Other TLS features are still used but provide no security benefits in absence of the above
     * gaps. For example, an insecure TLS connection is capable of negotiating HTTP/2 with ALPN and
     * it also has a regular-looking handshake.
     *
     * **This feature is not supported on Android API levels less than 24.** Prior releases lacked
     * a mechanism to trust some hosts and not others.
     *

                      "tls_params": {
                        "tls_minimum_protocol_version": "TLSv1_2",
                        "tls_maximum_protocol_version": "TLSv1_3"
                      },
                      "alpn_protocols": [
                        "istio-peer-exchange",
                        "istio"
                      ],
                      "tls_certificate_sds_secret_configs": [
                        {

    val response = call.execute()
    assertThat(response.body.string()).isEqualTo("success")
  }

  /**
   * Tests that use this will fail unless boot classpath is set. Ex. `-Xbootclasspath/p:/tmp/alpn-boot-8.0.0.v20140317`
   */
  private fun enableProtocol(protocol: Protocol) {
    enableTls()
    client =
      client.newBuilder()
        .protocols(listOf(protocol, Protocol.HTTP_1_1))
        .build()

    will use reflection to extract the `TrustManager` from the
    `SSLSocketFactory`.
 *  New: Support prerelease Java 9. This gets ALPN from the platform rather than
    relying on the alpn-boot bootclasspath override.
 *  New: `HttpLoggingInterceptor` now logs connection failures.
 *  New: Upgrade to Okio 1.8.0.

     ```xml
     <dependency>

     *
     * If multiple protocols are specified, [ALPN][alpn] will be used to negotiate a transport.
     * Protocol negotiation is only attempted for HTTPS URLs.
     *
     * [Protocol.HTTP_1_0] is not supported in this set. Requests are initiated with `HTTP/1.1`. If
     * the server responds with `HTTP/1.0`, that will be exposed by [Response.protocol].
     *
     * [alpn]: http://tools.ietf.org/html/draft-ietf-tls-applayerprotoneg

     *     represented as a combination of scheme, host and port. When empty, the origin is that of
     *     the `streamId`.
     * @param protocol an ALPN protocol, such as `h2`.
     * @param host an IP address or hostname.
     * @param port the IP port associated with the service.
     * @param maxAge time in seconds that this alternative is considered fresh.
     */

    5.x upgrade as an opportunity to remove very obsolete APIs.
 *  Fix: Recover gracefully when Android's `NativeCrypto` crashes with `"ssl == null"`. This occurs
    when OkHttp retrieves ALPN state on a closed connection.
 *  Upgrade: [Kotlin 1.6.21][kotlin_1_6_21].
 *  Upgrade: [Okio 3.1.0][okio_3_1_0].


## Version 5.0.0-alpha.6

_2022-03-14_