* create, cache and return" pattern. For further improvements, use {@link LoadingCache} and its
   * {@link LoadingCache#get(Object) get(K)} method instead of this one.
   *
   * <p>Among the improvements that this method and {@code LoadingCache.get(K)} both provide are:
   *
   * <ul>
   *   <li>{@linkplain LoadingCache#get(Object) awaiting the result of a pending load} rather than
   *       starting a redundant one

func getReqAccessKeyV4(r *http.Request, region string, stype serviceType) (auth.Credentials, bool, APIErrorCode) {
	ch, s3Err := parseCredentialHeader("Credential="+r.Form.Get(xhttp.AmzCredential), region, stype)
	if s3Err != ErrNone {
		// Strip off the Algorithm prefix.
		v4Auth := strings.TrimPrefix(r.Header.Get("Authorization"), signV4Algorithm)
		authFields := strings.Split(strings.TrimSpace(v4Auth), ",")
		if len(authFields) != 3 {

Specifically, to see Uvicorn, Starlette and FastAPI compared together (among many other tools).

The simpler the problem solved by the tool, the better performance it will get. And most of the benchmarks don't test the additional features provided by the tool.

The hierarchy is like:

* **Uvicorn**: an ASGI server
    * **Starlette**: (uses Uvicorn) a web microframework

  public val status: String

  public val code: Int
    get() {
      val statusParts = status.split(' ', limit = 3)
      require(statusParts.size >= 2) { "Unexpected status: $status" }
      return statusParts[1].toInt()
    }

  public val message: String
    get() {
      val statusParts = status.split(' ', limit = 3)

    EnumBiMap<Currency, Country> bimap2 = EnumBiMap.create(bimap1);
    assertEquals(Country.CANADA, bimap2.get(Currency.DOLLAR));
    assertEquals(bimap1, bimap2);
    bimap2.inverse().put(Country.SWITZERLAND, Currency.FRANC);
    assertEquals(Country.SWITZERLAND, bimap2.get(Currency.FRANC));
    assertNull(bimap1.get(Currency.FRANC));
    assertFalse(bimap2.equals(bimap1));

    /* Test that it can be empty. */

    switch (end - start) {
      case 0:
        return BigInteger.ONE;
      case 1:
        return nums.get(start);
      case 2:
        return nums.get(start).multiply(nums.get(start + 1));
      case 3:
        return nums.get(start).multiply(nums.get(start + 1)).multiply(nums.get(start + 2));
      default:
        // Otherwise, split the list in half and recursively do this.

우리 역시 이제부터 메소드를 "**작동**"이라고 부를 것입니다.

#### *경로 작동 데코레이터* 정의

{* ../../docs_src/first_steps/tutorial001.py hl[6] *}

`@app.get("/")`은 **FastAPI**에게 바로 아래에 있는 함수가 다음으로 이동하는 요청을 처리한다는 것을 알려줍니다.

* 경로 `/`
* <abbr title="HTTP GET 메소드"><code>get</code> 작동</abbr> 사용

/// info | `@decorator` 정보

이 `@something` 문법은 파이썬에서 "데코레이터"라 부릅니다.

{* ../../docs_src/first_steps/tutorial001.py h1[6] *}

`@app.get("/")` 告訴 **FastAPI** 那個函式負責處理請求：

* 路徑 `/`
* 使用 <abbr title="HTTP GET 方法"><code>get</code>操作</abbr>

/// info | `@decorator` Info

Python 中的 `@something` 語法被稱為「裝飾器」。

你把它放在一個函式上面。像一個漂亮的裝飾帽子（我猜這是術語的來源）。

一個「裝飾器」會對下面的函式做一些事情。

在這種情況下，這個裝飾器告訴 **FastAPI** 那個函式對應於 **路徑** `/` 和 **操作** `get`.

這就是「**路徑操作裝飾器**」。

///

你也可以使用其他的操作：

        assertTrue(execJob.jvmOptions.get(0).startsWith("-Xlog:gc*,gc+age=trace,safepoint:file="));
        assertTrue(execJob.jvmOptions.get(0).contains("gc-test.log"));

        // Test with custom logFilePath
        execJob.jvmOptions.clear();
        execJob.logFilePath("/custom/path");
        result = execJob.gcLogging();
        assertTrue(execJob.jvmOptions.get(0).contains("/custom/path"));
    }

    assertEquals(removalListener.size(), stats.evictionCount());
    assertEquals(computeCount.get(), stats.loadSuccessCount());
    assertEquals(exceptionCount.get() + computeNullCount.get(), stats.loadExceptionCount());
    // each computed value is still in the cache, or was passed to the removal listener
    assertEquals(computeCount.get(), cache.size() + removalListener.size());
  }

  @GwtIncompatible // NullPointerTester