.url(url)
        .build();
    try (Response response = client.newCall(request).execute()) {
      String responseSource = response.networkResponse() != null ? ("(network: "
          + response.networkResponse().code()
          + " over "
          + response.protocol()
          + ")") : "(cache)";
      int responseCode = response.code();

          e: IOException,
        ) {
          println("failed: $e")
        }

        override fun onResponse(
          call: Call,
          response: Response,
        ) {
          println("response: ${response.code}")
          response.close()
        }
      },
    )
  }

        .build()

    client.newCall(request).execute().use { response ->
      if (!response.isSuccessful) throw IOException("Unexpected code $response")

      println("Server: ${response.header("Server")}")
      println("Date: ${response.header("Date")}")
      println("Vary: ${response.headers("Vary")}")
    }
  }
}

fun main() {
  AccessHeaders().run()

        override fun onResponse(
          call: Call,
          response: Response,
        ) {
          response.use {
            if (!response.isSuccessful) throw IOException("Unexpected code $response")

            for ((name, value) in response.headers) {
              println("$name: $value")
            }

            println(response.body.string())
          }
        }
      },
    )
  }
}

    val call = client.newCall(request)
    val response =
      Response.Builder().request(request).code(200).message("").protocol(Protocol.HTTP_2)
        .build()
    val listener = loggingEventListenerFactory.create(call)
    listener.cacheConditionalHit(call, response)
    listener.cacheHit(call, response)
    listener.cacheMiss(call)
    listener.satisfactionFailure(call, response)
    logRecorder

    "info": {
        "title": "FastAPI",
        "version": "0.1.0"
    },
    "paths": {
        "/items/": {
            "get": {
                "responses": {
                    "200": {
                        "description": "Successful Response",
                        "content": {
                            "application/json": {



...
```

#### OpenAPI dùng để làm gì?

    webSocket = slackApi.rtm(rtmStartResponse.url, this);
  }

  // TODO(jwilson): can I read the response body? Do I have to?
  //                the body from slack is a 0-byte-buffer
  @Override public synchronized void onOpen(WebSocket webSocket, Response response) {
    System.out.println("onOpen: " + response);
  }

  // TOOD(jwilson): decode incoming messages and dispatch them somewhere.

        SecDispatcher.ValidationResponse response = secDispatcher.validateConfiguration();
        if (!response.isValid() || context.invokerRequest.options().verbose().orElse(false)) {
            dumpResponse(context, "", response);
        }
        return response.isValid();
    }

    protected void dumpResponse(

        .url("https://en.wikipedia.org/w/index.php")
        .post(formBody)
        .build();

    try (Response response = client.newCall(request).execute()) {
      if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

      System.out.println(response.body().string());
    }
  }

  public static void main(String... args) throws Exception {
    new PostForm().run();
  }

  @Test
  fun testOkHttpDirect() {
    testRequest {
      val client = OkHttpClient()

      val response =
        client.newCall(
          Request((mockServer.endpoint + "/person?name=peter").toHttpUrl()),
        ).execute()

      assertThat(response.body.string()).contains("Peter the person")
      assertThat(response.protocol).isEqualTo(Protocol.HTTP_1_1)
    }
  }

  @Test
  fun testOkHttpProxied() {