}

  private fun send404(
    stream: Http2Stream,
    path: String,
  ) {
    val responseHeaders =
      listOf(
        Header(":status", "404"),
        Header(":version", "HTTP/1.1"),
        Header("content-type", "text/plain"),
      )
    stream.writeHeaders(
      responseHeaders = responseHeaders,
      outFinished = false,
      flushHeaders = false,
    )
    val out = stream.sink.buffer()

        sink.writeDecimalLong((responseHeaders.size + 2).toLong()).writeByte('\n'.code)
        for (i in 0 until responseHeaders.size) {
          sink
            .writeUtf8(responseHeaders.name(i))
            .writeUtf8(": ")
            .writeUtf8(responseHeaders.value(i))
            .writeByte('\n'.code)
        }
        sink

        assertNotNull("Allow-Origin header should be set", responseHeaders.get("Access-Control-Allow-Origin"));
        assertNotNull("Allow-Methods header should be set", responseHeaders.get("Access-Control-Allow-Methods"));
        assertNotNull("Allow-Headers header should be set", responseHeaders.get("Access-Control-Allow-Headers"));
        assertNotNull("Max-Age header should be set", responseHeaders.get("Access-Control-Max-Age"));

  }

  @Test
  fun messagesCompressedWhenConfigured() {
    val headers = headersOf("Sec-WebSocket-Extensions", "permessage-deflate")
    client.initWebSocket(random, responseHeaders = headers)
    server.initWebSocket(random, responseHeaders = headers)
    val message = repeat('a', RealWebSocket.DEFAULT_MINIMUM_DEFLATE_SIZE.toInt())
    server.webSocket!!.send(message)
    taskFaker.runTasks()

          if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

          Headers responseHeaders = response.headers();
          for (int i = 0; i < responseHeaders.size(); i++) {
            System.out.println(responseHeaders.name(i) + ": " + responseHeaders.value(i));
          }

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

   *     response body exists and will be written immediately.
   */
  @Throws(IOException::class)
  fun writeHeaders(
    responseHeaders: List<Header>,
    outFinished: Boolean,
    flushHeaders: Boolean,
  ) {
    assertLockNotHeld()

    var flushHeaders = flushHeaders
    withLock {
      this.hasResponseHeaders = true

    val responseHeaders = response.headers
    assertThat(LinkedHashSet(responseHeaders.values("A"))).isEqualTo(newSet("c", "e"))
    assertThat(LinkedHashSet(responseHeaders.values("a"))).isEqualTo(newSet("c", "e"))
    assertThat(responseHeaders.name(0)).isEqualTo("A")
    assertThat(responseHeaders.value(0)).isEqualTo("c")
    assertThat(responseHeaders.name(1)).isEqualTo("B")

      return false
    }

    @Synchronized override fun onHeaders(
      streamId: Int,
      responseHeaders: List<Header>,
      last: Boolean,
    ): Boolean {
      assertThat(streamId).isEqualTo(2)
      assertThat(last).isTrue()
      events.add(responseHeaders)
      notifyAll()
      return false
    }

    @Synchronized override fun onData(
      streamId: Int,

        ) = TODO()
      }
  }

  private fun newCookieHandler(): CookieHandler =
    object : CookieHandler() {
      override fun put(
        uri: URI?,
        responseHeaders: MutableMap<String, MutableList<String>>?,
      ) = TODO()

      override fun get(
        uri: URI?,
        requestHeaders: MutableMap<String, MutableList<String>>?,

You can declare a parameter of type `Response` in your *path operation function* (as you can do for cookies).

And then you can set headers in that *temporal* response object.

{* ../../docs_src/response_headers/tutorial002.py hl[1, 7:8] *}

And then you can return any object you need, as you normally would (a `dict`, a database model, etc).