// Check auth here (otherwise r.Form will have unexpected values from
	// the call to `parseForm` below), but return failure only after we are
	// able to validate that it is a valid STS request, so that we are able
	// to send an appropriate audit log.
	user, apiErrCode := checkAssumeRoleAuth(ctx, r)

	if err := parseForm(r); err != nil {
		writeSTSErrorResponse(ctx, w, ErrSTSInvalidParameterValue, err)
		return
	}

begins. Communication blocks until the send can proceed.
A send on an unbuffered channel can proceed if a receiver is ready.
A send on a buffered channel can proceed if there is room in the buffer.
A send on a closed channel proceeds by causing a <a href="#Run_time_panics">run-time panic</a>.
A send on a <code>nil</code> channel blocks forever.
</p>

<pre>
ch &lt;- 3  // send value 3 to channel ch
</pre>

<p>

* Verificar se existe um parâmetro de _query_ opcional nomeado como `q` (como em `http://127.0.0.1:8000/items/foo?q=somequery`) para requisições `GET`.
    * Como o parâmetro `q` é declarado com `= None`, ele é opcional.
    * Sem o `None` ele poderia ser obrigatório (como o corpo no caso de `PUT`).
* Para requisições `PUT` para `/items/{item_id}`, lerá o corpo como JSON e:
    * Verifica que tem um atributo obrigatório `name` que deve ser `str`.

### Required, can be `None` { #required-can-be-none }

You can declare that a parameter can accept `None`, but that it's still required. This would force clients to send a value, even if the value is `None`.

To do that, you can declare that `None` is a valid type but simply do not declare a default value:

{* ../../docs_src/query_params_str_validations/tutorial006c_an_py310.py hl[9] *}

Se você se sente perdido com todo esse assunto de **"expressão regular"**, não se preocupe. Esse é um assunto complicado para a maioria das pessoas. Você ainda pode fazer muitas coisas sem utilizar expressões regulares.

Mas assim que você precisar e já tiver aprendido sobre, saiba que você poderá usá-las diretamente no **FastAPI**.

## Valores padrão

  // These properties are only accessed by the thread executing the call.

  /** Initialized in [callStart]. */
  private var callStackTrace: Any? = null

  /** Finds an exchange to send the next request and receive the next response. */
  private var exchangeFinder: ExchangeFinder? = null

  var connection: RealConnection? = null
    private set
  private var timeoutEarlyExit = false

  /**

        int bufferCacheSize = delegatingConfig.getBufferCacheSize();
        int notifyBufferSize = delegatingConfig.getNotifyBufferSize();

        // Then
        assertEquals(8192, sendBufferSize, "Should delegate send buffer size");
        assertEquals(8192, receiveBufferSize, "Should delegate receive buffer size");
        assertEquals(65536, maximumBufferSize, "Should delegate maximum buffer size");

    end
    operation ->> client: Return response to client
    Note over client,operation: Response is already sent, can't change it anymore
    opt Tasks
        operation -->> tasks: Send background tasks
    end
    opt Raise other exception
        tasks -->> dep: Raise other exception
    end
    Note over dep: After yield
    opt Handle other exception

    end

    operation ->> client: Return response to client
    Note over client,operation: Response is already sent, can't change it anymore
    opt Tasks
        operation -->> tasks: Send background tasks
    end
    opt Raise other exception
        tasks -->> tasks: Handle exceptions in the background task code
    end
```

/// info

pkg go/types, method (*TypeParamList) TypeParams() iter.Seq[*TypeParam] #66626
pkg go/types, method (*Union) Terms() iter.Seq[*Term] #66626
pkg hash/maphash, func Comparable[$0 comparable](Seed, $0) uint64 #54670
pkg hash/maphash, func WriteComparable[$0 comparable](*Hash, $0) #54670
pkg log/slog, method (*LevelVar) AppendText([]uint8) ([]uint8, error) #62384