assumeNetwork()

    val request = Request.Builder().url("https://api.twitter.com/robots.txt").build()

    val clientCertificates =
      HandshakeCertificates.Builder()
        .addPlatformTrustedCertificates()
        .apply {
          if (Build.VERSION.SDK_INT >= 24) {
            addInsecureHost(server.hostName)
          }
        }
        .build()

    client =
      client.newBuilder()

    [our DevServer sample][dev_server]:

    ```kotlin
    val clientCertificates = HandshakeCertificates.Builder()
        .addPlatformTrustedCertificates()
        .addInsecureHost("localhost")
        .build()

    val client = OkHttpClient.Builder()
        .sslSocketFactory(clientCertificates.sslSocketFactory(), clientCertificates.trustManager)

    builder = builder.heldCertificate(heldCertificate, heldCertificate.certificate)
    builder = builder.addTrustedCertificate(heldCertificate.certificate)
    builder = builder.addPlatformTrustedCertificates()
    val handshakeCertificates: HandshakeCertificates = builder.build()
  }

  @Test
  fun heldCertificate() {
    val heldCertificate: HeldCertificate = HeldCertificate.Builder().build()