headers = Headers.headersOf("content-type", "application/json"),
      ),
    )
    server.enqueue(
      MockResponse(
        body =
          """
          |data: hey
          |
          |
          """.trimMargin(),
        headers = Headers.headersOf("content-type", "text/event-stream"),
      ),
    )

[2020-01-01 00:00:00] >> 0x00000003    47 HEADERS       END_STREAM|END_HEADERS
[2020-01-01 00:00:00] << 0x00000000     6 SETTINGS
[2020-01-01 00:00:00] << 0x00000000     0 SETTINGS      ACK
[2020-01-01 00:00:00] << 0x00000000     4 WINDOW_UPDATE
[2020-01-01 00:00:00] >> 0x00000000     0 SETTINGS      ACK
[2020-01-01 00:00:00] << 0x00000003   322 HEADERS       END_HEADERS
[2020-01-01 00:00:00] << 0x00000003   288 DATA

		if e != nil {
			t.Errorf("(%d) failed to create http.Request, got %v", i, e)
		}

		// Do the same for the headers.
		for key, value := range testCase.headers {
			req.Header.Set(key, value)
		}

		// parse form.
		req.ParseForm()

		// Check if it matches!
		err := doesPresignedSignatureMatch(payloadSHA256, req, testCase.region, serviceS3)

        .url(server.url("/"))
        .header("Accept", "text/plain")
        .build()
    val response = client.newCall(request).execute()
    assertThat(response.code).isEqualTo(200)
    assertThat(response.body.string()).isEqualTo("hello, OkHttp")

    val recorded = server.takeRequest()
    assertThat(recorded.headers["Accept"]).isEqualTo("text/plain")
    assertThat(recorded.headers["Accept-Encoding"]).isEqualTo("gzip")

  var canUseHeaderValue = true
  var headerValue: String? = null

  loop@ for (i in 0 until headers.size) {
    val name = headers.name(i)
    val value = headers.value(i)

    when {
      name.equals("Cache-Control", ignoreCase = true) -> {
        if (headerValue != null) {
          // Multiple cache-control headers means we can't use the raw value.
          canUseHeaderValue = false
        } else {

It might also help avoid confusion for new developers that see an unused parameter in your code and could think it's unnecessary.

///

/// info

In this example we use invented custom headers `X-Key` and `X-Token`.

But in real cases, when implementing security, you would get more benefits from using the integrated [Security utilities (the next chapter)](../security/index.md){.internal-link target=_blank}.

///

* `path` - The file path to the file to stream.
* `headers` - Any custom headers to include, as a dictionary.
* `media_type` - A string giving the media type. If unset, the filename or path will be used to infer a media type.
* `filename` - If set, this will be included in the response `Content-Disposition`.

File responses will include appropriate `Content-Length`, `Last-Modified` and `ETag` headers.

{* ../../docs_src/header_param_models/tutorial001_an_py310.py hl[9:14,18] *}

O **FastAPI** irá **extrair** os dados de **cada campo** a partir dos **cabeçalhos** da requisição e te retornará o modelo do Pydantic que você definiu.

### Checando a documentação

Você pode ver os headers necessários na interface gráfica da documentação em `/docs`:

  forObsoleteRfc2965: Boolean,
): String = cookie.toString(forObsoleteRfc2965)

internal fun addHeaderLenient(
  builder: Headers.Builder,
  line: String,
): Headers.Builder = builder.addLenient(line)

internal fun addHeaderLenient(
  builder: Headers.Builder,
  name: String,
  value: String,
): Headers.Builder = builder.addLenient(name, value)

internal fun cacheGet(
  cache: Cache,
  request: Request,

        // Mock getHeaderFields to return our headers
        Map<String, List<String>> allHeaders = headers != null ? new HashMap<>(headers) : new HashMap<>();
        allHeaders.put(null, Collections.singletonList(statusLine)); // Status line
        when(conn.getHeaderFields()).thenReturn(allHeaders);

        // Mock individual header access by both string key and index
        if (headers != null) {
            // Mock by header name