public void run() throws Exception {
    File socketFile = new File("/tmp/ClientAndServer.sock");
    socketFile.delete(); // Clean up from previous runs.

    MockWebServer server = new MockWebServer();
    server.setServerSocketFactory(new UnixDomainServerSocketFactory(socketFile));
    server.setProtocols(Collections.singletonList(Protocol.H2_PRIOR_KNOWLEDGE));
    server.enqueue(new MockResponse().setBody("hello"));
    server.start();

  fun getPort(): Int = port

  fun toProxyAddress(): Proxy {
    before() // This implicitly starts the delegate.
    return delegate.proxyAddress
  }

  @JvmName("-deprecated_serverSocketFactory")
  fun setServerSocketFactory(serverSocketFactory: ServerSocketFactory) {
    delegate.serverSocketFactory = serverSocketFactory
  }

  fun url(path: String): HttpUrl {
    before() // This implicitly starts the delegate.