.header("Content-Type", "text/plain-ish")
            .build(),
        )
      }
    server.enqueue(MockResponse())
    client.newCall(
      request()
        .post("Hi?".toRequestBody(PLAIN))
        .build(),
    ).execute()
    applicationLogs
      .assertLogEqual("--> POST $url")
      .assertLogEqual("Content-Type: text/plain; charset=utf-8")
      .assertLogEqual("Content-Length: 3")

    assertFailsWith<IllegalArgumentException> {
      Request.Builder().method("GET", "abc".toRequestBody("text/plain".toMediaType()))
    }
  }

  @Test
  fun head() {
    server.enqueue(
      MockResponse(
        headers = headersOf("Content-Type", "text/plain"),
      ),
    )
    val request =
      Request.Builder()
        .url(server.url("/"))
        .head()

       *
       * Example:
       * ```
       * --> POST /greeting http/1.1
       * Host: example.com
       * Content-Type: plain/text
       * Content-Length: 3
       * --> END POST
       *
       * <-- 200 OK (22ms)
       * Content-Type: plain/text
       * Content-Length: 6
       * <-- END HTTP
       * ```
       */
      HEADERS,

      /**

    subgraph Client Node
        Client
        CZ["Ztunnel"]
    end
    subgraph Server Node
        Server
        SZ["Ztunnel"]
    end
    Client--Plain-->CZ
    CZ-."HBONE (target)".->Server
    CZ--"HBONE (actual)"-->SZ
    SZ--Plain-->Server
```

### Pooling

User connections can be multiplexed over shared HBONE connections.
This is done through standard HTTP/2 pooling.

    val call =
      client.newCall(
        Request(
          url = server.url("/foo"),
          body =
            object : RequestBody() {
              override fun contentType(): MediaType = "text/plain; charset=utf-8".toMediaType()

              override fun writeTo(sink: BufferedSink) {
                sink.write(postBytes)
              }
            },
        ),
      )

{!../../../docs_src/path_operation_advanced_configuration/tutorial006.py!}
```

In this example, we didn't declare any Pydantic model. In fact, the request body is not even <abbr title="converted from some plain format, like bytes, into Python objects">parsed</abbr> as JSON, it is read directly as `bytes`, and the function `magic_data_reader()` would be in charge of parsing it in some way.

=== "Python 3.8+"

    ```Python hl_lines="1  20"
    {!> ../../../docs_src/extra_models/tutorial004.py!}
    ```

## Response with arbitrary `dict`

You can also declare a response using a plain arbitrary `dict`, declaring just the type of the keys and values, without using a Pydantic model.

This is useful if you don't know the valid field/attribute names (that would be needed for a Pydantic model) beforehand.

```

### `HTMLResponse`

Takes some text or bytes and returns an HTML response, as you read above.

### `PlainTextResponse`

Takes some text or bytes and returns an plain text response.

```Python hl_lines="2  7  9"
{!../../../docs_src/custom_response/tutorial005.py!}
```

### `JSONResponse`

Takes some data and returns an `application/json` encoded response.

  // +optional
  repeated AllowedCSIDriver allowedCSIDrivers = 23;

  // allowedUnsafeSysctls is a list of explicitly allowed unsafe sysctls, defaults to none.
  // Each entry is either a plain sysctl name or ends in "*" in which case it is considered
  // as a prefix of allowed sysctls. Single * means all unsafe sysctls are allowed.
  // Kubelet has to allowlist all allowed unsafe sysctls explicitly to avoid rejection.

Do mesmo modo, você pode sobreescrever o `HTTPException`.

Por exemplo, você pode querer retornar uma *response* em *plain text* ao invés de um JSON para os seguintes erros:

```Python hl_lines="3-4  9-11  22"
{!../../../docs_src/handling_errors/tutorial004.py!}
```

!!! note "Detalhes Técnicos"