* printing space backward on the same printing line. (Applicable also to display devices.)
   *
   * @since 8.0
   */
  public static final byte BS = 8;

  /**
   * Horizontal Tabulation ('\t'): A format effector which controls the movement of the printing
   * position to the next in a series of predetermined positions along the printing line.
   * (Applicable also to display devices and the skip function on punched cards.)
   *

        .post(sleepingRequestBody(500))
        .build()
    val call = client.newCall(request)
    call.timeout().timeout(250, TimeUnit.MILLISECONDS)
    assertFailsWith<IOException> {
      call.execute()
    }.also { expected ->
      assertThat(expected.message).isEqualTo("timeout")
      assertThat(call.isCanceled()).isTrue()
    }
  }

  @Test
  fun timeoutWritingRequestWithEnqueue() {
    server.enqueue(MockResponse())

Including external libraries also based on Pydantic, as <abbr title="Object-Relational Mapper">ORM</abbr>s, <abbr title="Object-Document Mapper">ODM</abbr>s for databases.

Um Header zu deklarieren, müssen Sie `Header` verwenden, da diese Parameter sonst als Query-Parameter interpretiert werden würden.

///

## Automatische Konvertierung

`Header` hat weitere Funktionalität, zusätzlich zu der, die `Path`, `Query` und `Cookie` bereitstellen.

Die meisten Standard-Header benutzen als Trennzeichen einen Bindestrich, auch bekannt als das „Minus-Symbol“ (`-`).

Deklarieren wir also `tags` als Set von Strings.

{* ../../docs_src/body_nested_models/tutorial003_py310.py hl[12] *}

Jetzt, selbst wenn Sie einen Request mit duplizierten Daten erhalten, werden diese zu einem Set eindeutiger Dinge konvertiert.

Und wann immer Sie diese Daten ausgeben, selbst wenn die Quelle Duplikate hatte, wird es als Set von eindeutigen Dingen ausgegeben.

      clientWriter.writeClose(98724976, "Hello".encodeUtf8())
    }.also { expected ->
      assertThat(expected.message).isEqualTo("Code must be in range [1000,5000): 98724976")
    }
  }

  @Test fun closeReservedThrows() {
    assertFailsWith<IllegalArgumentException> {
      clientWriter.writeClose(1005, "Hello".encodeUtf8())
    }.also { expected ->

/// info

The parameter `response_class` will also be used to define the "media type" of the response.

In this case, the HTTP header `Content-Type` will be set to `text/html`.

And it will be documented as such in OpenAPI.

///

### Return a `Response` { #return-a-response }

Let's take this application as example:

{* ../../docs_src/query_params_str_validations/tutorial001_py310.py hl[7] *}

The query parameter `q` is of type `str | None`, that means that it's of type `str` but could also be `None`, and indeed, the default value is `None`, so FastAPI will know it's not required.

/// note

FastAPI will know that the value of `q` is not required because of the default value `= None`.

# GraphQL { #graphql }

As **FastAPI** is based on the **ASGI** standard, it's very easy to integrate any **GraphQL** library also compatible with ASGI.

You can combine normal FastAPI *path operations* with GraphQL on the same application.

/// tip

**GraphQL** solves some very specific use cases.

It has **advantages** and **disadvantages** when compared to common **web APIs**.

    assertThat(request.tag(Any::class.java)).isNull()
    assertThat(request.tag(UUID::class.java)).isNull()
    assertThat(request.tag(String::class.java)).isNull()

    // Alternate access APIs also work.
    assertThat(request.tag<String>()).isNull()
    assertThat(request.tag(String::class)).isNull()
  }

  @Test
  fun defaultTag() {
    val tag = UUID.randomUUID()
    val request =