/// note | Technical Details

You could also use `from starlette.middleware.cors import CORSMiddleware`.

**FastAPI** provides several middlewares in `fastapi.middleware` just as a convenience for you, the developer. But most of the available middlewares come directly from Starlette.

    void testEncodeSourceOffsetBeyondLength() {
        // Test with source offset + length exceeding source array bounds
        byte[] data = { 0x01, 0x02 };
        // This constructor call itself should not throw an error, as it's just storing the values.
        // The error should occur when System.arraycopy is called.
        ByteEncodable encodable = new ByteEncodable(data, 1, 2); // off=1, len=2, data.length=2. 1+2 > 2

        byte[] dest = new byte[5];

   * - The second request discovers it "lost the race" and closes the connection it just opened.
   * - The second request uses the coalesced connection from request1.
   * - The coalesced connection is violently closed after servicing the first request.
   * - The second request discovers the coalesced connection is unhealthy just after acquiring it.
   */
  @Test
  fun coalescedConnectionDestroyedAfterAcquire() {

    }
  }

  /**
   * Moves a file from one path to another. This method can rename a file and/or move it to a
   * different directory. In either case {@code to} must be the target path for the file itself; not
   * just the new name for the file or the path to the new parent directory.
   *
   * <p><b>{@link java.nio.file.Path} equivalent:</b> {@link java.nio.file.Files#move}.
   *
   * @param from the source file

        writeByte('%'.code)
        writeByte(HEX_DIGITS[b shr 4 and 0xf].code)
        writeByte(HEX_DIGITS[b and 0xf].code)
      }
    } else {
      // This character doesn't need encoding. Just copy it over.
      writeUtf8CodePoint(codePoint)
    }
    i += Character.charCount(codePoint)
  }
}

/**
 * Returns a substring of `input` on the range `[pos..limit)` with the following

But you should first read the **Tutorial - User Guide** (what you are reading right now).

    KOqkqm57TH2H3eDJAkSnh6/DNFu0Qg==
    -----END CERTIFICATE-----
    """.trimIndent().decodeCertificatePem()

  private val client: OkHttpClient

  init {
    // This implementation just embeds the PEM files in Java strings; most applications will
    // instead read this from a resource file that gets bundled with the application.
    val certificates =
      HandshakeCertificates
        .Builder()

The marker `@pytest.mark.anyio` tells pytest that this test function should be called asynchronously:

{* ../../docs_src/async_tests/test_main.py hl[7] *}

/// tip

Note that the test function is now `async def` instead of just `def` as before when using the `TestClient`.

///

Then we can create an `AsyncClient` with the app, and send async requests to it, using `await`.

{* ../../docs_src/async_tests/test_main.py hl[9:12] *}

## Quick Start

    String message = "Waited " + timeout + " " + unit.toString().toLowerCase(Locale.ROOT);
    // Only report scheduling delay if larger than our spin threshold - otherwise it's just noise
    if (remainingNanos + SPIN_THRESHOLD_NANOS < 0) {
      // We over-waited for our timeout.
      message += " (plus ";
      long overWaitNanos = -remainingNanos;