HandshakeCertificates serverCertificates = new HandshakeCertificates.Builder()
        .heldCertificate(localhostCertificate)
        .build();
    MockWebServer server = new MockWebServer();
    server.useHttps(serverCertificates.sslSocketFactory(), false);
    server.enqueue(new MockResponse());

    HandshakeCertificates clientCertificates = new HandshakeCertificates.Builder()
        .addTrustedCertificate(localhostCertificate.certificate())