* connection the socket may be shared by multiple concurrent calls.
   */
  fun socket(): Socket

  /**
   * Returns the TLS handshake used to establish this connection, or null if the connection is not
   * HTTPS.
   */
  fun handshake(): Handshake?

  /**
   * Returns the protocol negotiated by this connection, or [Protocol.HTTP_1_1] if no protocol

    response.use {
      assertEquals(Protocol.HTTP_2, response.protocol)
      if (Build.VERSION.SDK_INT >= 29) {
        assertEquals(TlsVersion.TLS_1_3, response.handshake?.tlsVersion)
      } else {
        assertEquals(TlsVersion.TLS_1_2, response.handshake?.tlsVersion)
      }
      assertEquals(200, response.code)
      assertTrue(socketClass?.startsWith("com.android.org.conscrypt.") == true)
    }
  }

  @Test

| Java                                | Kotlin                          |
| :---------------------------------- | :------------------------------ |
| Handshake.get(SSLSession)           | SSLSession.handshake()          |
| Headers.of(Map<String, String>)     | Map<String, String>.toHeaders() |
| HttpUrl.get(String)                 | String.toHttpUrl()              |

      printEvent("connectStart");
    }

    @Override public void secureConnectStart(Call call) {
      printEvent("secureConnectStart");
    }

    @Override public void secureConnectEnd(Call call, Handshake handshake) {
      printEvent("secureConnectEnd");
    }

    @Override public void connectEnd(
        Call call, InetSocketAddress inetSocketAddress, Proxy proxy, Protocol protocol) {
      printEvent("connectEnd");

    .build();
```

### Debugging TLS Handshake Failures

The TLS handshake requires clients and servers to share a common TLS version and cipher suite. This
depends on the JVM or Android version, OkHttp version, and web server configuration. If there is no
common cipher suite and TLS version, your call will fail like this:

```
Caused by: javax.net.ssl.SSLProtocolException: SSL handshake aborted: ssl=0x7f2719a89e80:

    val request = Request(server.url("/"))

    val response = client.newCall(request).execute()

    response.use {
      assertEquals(200, response.code)
      assertEquals(TlsVersion.TLS_1_3, response.handshake?.tlsVersion)
      assertEquals(Protocol.HTTP_2, response.protocol)

      assertThat(response.exchangeAccessor!!.connectionAccessor.socket())
        .isInstanceOf<SSLSocketImpl>()
    }
  }

  @Test

  private val retryableException = SSLHandshakeException("Simulated handshake exception")

  @RegisterExtension
  val clientTestRule = OkHttpClientTestRule()

  private var client = clientTestRule.newClient()

  @AfterEach internal fun tearDown() {
    factory.close()
  }

  @Test fun nonRetryableIOException() {
    val exception = IOException("Non-handshake exception")
    assertThat(retryTlsHandshake(exception)).isFalse()
  }

  }

  override fun secureConnectStart(call: Call) {
    logWithTime("secureConnectStart")
  }

  override fun secureConnectEnd(
    call: Call,
    handshake: Handshake?,
  ) {
    logWithTime("secureConnectEnd: $handshake")
  }

  override fun connectEnd(
    call: Call,
    inetSocketAddress: InetSocketAddress,
    proxy: Proxy,
    protocol: Protocol?,
  ) {

      printEvent("connectStart");
    }

    @Override public void secureConnectStart(Call call) {
      printEvent("secureConnectStart");
    }

    @Override public void secureConnectEnd(Call call, Handshake handshake) {
      printEvent("secureConnectEnd");
    }

    @Override public void connectEnd(
        Call call, InetSocketAddress inetSocketAddress, Proxy proxy, Protocol protocol) {
      printEvent("connectEnd");

	public fun toString ()Ljava/lang/String;
}

public final class okhttp3/Handshake$Companion {
	public final fun -deprecated_get (Ljavax/net/ssl/SSLSession;)Lokhttp3/Handshake;
	public final fun get (Ljavax/net/ssl/SSLSession;)Lokhttp3/Handshake;
	public final fun get (Lokhttp3/TlsVersion;Lokhttp3/CipherSuite;Ljava/util/List;Ljava/util/List;)Lokhttp3/Handshake;
}