* specific length.
   *
   * <p>For example, if you need 1024-bit hash codes, you could join two {@link Hashing#sha512} hash
   * functions together: {@code Hashing.concatenating(Hashing.sha512(), Hashing.sha512())}.
   *
   * @since 19.0
   */
  public static HashFunction concatenating(
      HashFunction first, HashFunction second, HashFunction... rest) {

- [ ] Provide unit tests (under `<subproject>/src/test`) to verify logic.
- [ ] Update User Guide, DSL Reference, and Javadoc for public-facing changes.
- [ ] Ensure that tests pass sanity check: `./gradlew sanityCheck`.
- [ ] Ensure that tests pass locally: `./gradlew <changed-subproject>:quickTest`.

### Reviewing cheatsheet

不过，仍可以验证、转换与注释（使用 Pydantic 模型的请求体等）其它正常声明的参数。

但在某些特定情况下，还是需要提取 `Request` 对象。

## 直接使用 `Request` 对象

假设要在*路径操作函数*中获取客户端 IP 地址和主机。

此时，需要直接访问请求。

```Python hl_lines="1  7-8"
{!../../../docs_src/using_request_directly/tutorial001.py!}
```

把*路径操作函数*的参数类型声明为 `Request`，**FastAPI** 就能把 `Request` 传递到参数里。

!!! tip "提示"

    注意，本例除了声明请求参数之外，还声明了路径参数。

    因此，能够提取、验证路径参数、并转换为指定类型，还可以用 OpenAPI 注释。

                                  description: The Maglev load balancer implements
                                    consistent hashing to backend hosts.
                                  properties:
                                    tableSize:
                                      description: The table size for Maglev hashing.
                                      type: integer
                                  type: object

## Making your change

### Code change guidelines

All code contributions should contain the following:

* Create unit tests using [Spock](https://spockframework.org/spock/docs/2.0/index.html) for new classes or methods that you introduce.

Angenommen, Sie möchten auf die IP-Adresse/den Host des Clients in Ihrer *Pfadoperation-Funktion* zugreifen.

Dazu müssen Sie direkt auf den Request zugreifen.

```Python hl_lines="1  7-8"
{!../../../docs_src/using_request_directly/tutorial001.py!}
```

Durch die Deklaration eines *Pfadoperation-Funktionsparameters*, dessen Typ der `Request` ist, weiß **FastAPI**, dass es den `Request` diesem Parameter übergeben soll.

!!! tip "Tipp"

   * objects per entry.  Instead we use an open-addressed hash table.  This design is basically
   * equivalent to RegularImmutableSet, save that instead of having a hash table containing the
   * elements directly and null for empty positions, we store indices of the keys in the hash table,
   * and ABSENT for empty positions.  We then look up the keys in alternatingKeysAndValues.
   *

			}
		})
	}
}

// TestSipHashMod - test sip hash.
func TestSipHashMod(t *testing.T) {
	testCases := []struct {
		objectName string
		sipHash    int
	}{
		// cases which should pass the test.
		// passing in valid object name.
		{"object", 37},
		{"The Shining Script <v1>.pdf", 38},
		{"Cost Benefit Analysis (2009-2010).pptx", 59},
		{"117Gn8rfHL2ACARPAhaFd0AGzic9pUbIA/5OCn5A", 35},
		{"SHØRT", 49},

      verifyHostname(hostname, it)
    }
  }

  /**
   * This is like [toLowerCase] except that it does nothing if this contains any non-ASCII
   * characters. We want to avoid lower casing special chars like U+212A (Kelvin symbol) because
   * they can return ASCII characters that match real hostnames.
   */
  private fun String.asciiToLowercase(): String {
    return when {

      this.key = key;
      this.firstEntry = this;
      this.lastEntry = this;
      // Round expected values up to a power of 2 to get the table size.
      int tableSize = Hashing.closedTableSize(expectedValues, VALUE_SET_LOAD_FACTOR);

      @SuppressWarnings({"rawtypes", "unchecked"})
      @Nullable
      ValueEntry<K, V>[] hashTable = new @Nullable ValueEntry[tableSize];