* custom builds of OkHttp please include a qualifier your version name, like "4.7.0-mycompany.3".
   * The version string is configured in the root project's `build.gradle`.
   *
   * Note that OkHttp's runtime version may be different from the version specified in your
   * project's build file due to the dependency resolution features of your build tool.
   *
   * [semver]: https://semver.org
   */

/**
 * A domain name service that resolves IP addresses for host names. Most applications will use the
 * [system DNS service][SYSTEM], which is the default. Some applications may provide their own
 * implementation to use a different DNS server, to prefer IPv6 addresses, to prefer IPv4 addresses,
 * or to force a specific known IP address.
 *
 * Implementations of this interface must be safe for concurrent use.
 */
fun interface Dns {
  /**

    assertThat(response.isSuccessful).isTrue()

    val recordedRequest = server.takeRequest()
    assertThat(recordedRequest.handshakeServerNames).containsExactly(url.host)
  }

  /**
   * Use different hostnames for the TLS handshake (including SNI) and the HTTP request (in the
   * Host header).
   */
  @Test
  fun domainFronting() {
    val heldCertificate =
      HeldCertificate.Builder()

          file = null
        }
      }

      fileToClose?.closeQuietly()
    }
  }

  companion object {
    // TODO(jwilson): what to do about timeouts? They could be different and unfortunately when any
    //     timeout is hit we like to tear down the whole stream.

    private const val SOURCE_UPSTREAM = 1
    private const val SOURCE_FILE = 2

      |
      """.trimMargin()
    val heldCertificate = decode(certificatePem + pkcs8Pem)
    assertThat(heldCertificate.certificatePem()).isEqualTo(certificatePem)

    // Slightly different encoding
    if (platform.isBouncyCastle()) {
      assertThat(heldCertificate.privateKeyPkcs8Pem()).isEqualTo(bcPkcs8Pem)
    } else {
      assertThat(heldCertificate.privateKeyPkcs8Pem()).isEqualTo(pkcs8Pem)
    }

    This particularly-subtle bug was caused by us assigning each `OkHttpClient` instance its own
    `NullProxySelector` when an explicit proxy is configured. But we don't share connections when
    the proxy selectors are different. Ugh!


## Version 4.2.0

_2019-09-10_

 *  New: API to decode a certificate and private key to create a `HeldCertificate`. This accepts a

  }

  /**
   * When callers parse a URL with query components that aren't encoded, we shouldn't convert them
   * into a canonical form because doing so could be semantically different.
   */
  @Test
  fun queryCharactersNotReencodedWhenParsed() {
    val url = parse("http://host/?a=!$(),/:;?@[]\\^`{|}~")
    assertThat(url.toString()).isEqualTo("http://host/?a=!$(),/:;?@[]\\^`{|}~")

    assertFailsWith<IOException> {
      getResponse(newRequest("/foo"))
    }.also { expected ->
      when (expected) {
        is SSLHandshakeException -> {
          // Allow conscrypt to fail in different ways
          if (!platform.isConscrypt()) {
            assertThat(expected.cause!!).isInstanceOf<CertificateException>()
          }
        }
        is TlsFatalAlert -> {}
        else -> throw expected

   * limits, this call may be executed well before processing the request is able to begin.
   *
   * This will be invoked only once for a single [Call]. Retries of different routes or redirects
   * will be handled within the boundaries of a single [callStart] and [callEnd]/[callFailed] pair.
   */
  open fun callStart(call: Call) {
  }

  /**
   * Invoked prior to a proxy selection.

 * conventions. Both binary and source-incompatible changes are possible, including complete removal
 * of the experimental API.
 *
 * Do not use these APIs in modules that may be executed using a version of OkHttp different from
 * the version the module was compiled with.
 *
 * Do not use these APIs in published libraries.
 *
 * Do not use these APIs if you aren't willing to track changes to them.
 */
@MustBeDocumented