# Lifespan Events { #lifespan-events }

You can define logic (code) that should be executed before the application **starts up**. This means that this code will be executed **once**, **before** the application **starts receiving requests**.

The same way, you can define logic (code) that should be executed when the application is **shutting down**. In this case, this code will be executed **once**, **after** having handled possibly **many requests**.

@app.get("/items/{item_id}")
async def read_items(item_id: str):
    return items[item_id]


def test_read_items():
    # Before the lifespan starts, "items" is still empty
    assert items == {}

    with TestClient(app) as client:
        # Inside the "with TestClient" block, the lifespan starts and items added
        assert items == {"foo": {"name": "Fighters"}, "bar": {"name": "Tenders"}}

        response = client.get("/items/foo")

    @Timeout(5)
    public void testSessionLifecycle() throws Exception {
        SmbSessionImpl session = new SmbSessionImpl(mockContext, "testhost", "testdomain", mockTransport);

        // Test initial state - session starts with usage count > 0 due to transport.acquire()
        assertTrue(session.isInUse(), "New session should be in use due to transport acquisition");

        // Test additional acquire
        session.acquire();

## `fastapi dev` { #fastapi-dev }

Das Ausführen von `fastapi dev` startet den Entwicklermodus.

`Depends()` erhält einen `scope`-Parameter, der sein kann:

* `"function"`: startet die Abhängigkeit vor der *Pfadoperation-Funktion*, die den Request bearbeitet, beendet die Abhängigkeit nach dem Ende der *Pfadoperation-Funktion*, aber **bevor** die Response an den Client zurückgesendet wird. Die Abhängigkeitsfunktion wird also **um** die *Pfadoperation-**Funktion*** **herum** ausgeführt.

    return new Stopwatch(ticker);
  }

  /**
   * Creates (and starts) a new stopwatch using {@link System#nanoTime} as its time source.
   *
   * @since 15.0
   */
  public static Stopwatch createStarted() {
    return new Stopwatch().start();
  }

  /**
   * Creates (and starts) a new stopwatch, using the specified time source.
   *
   * @since 15.0
   */

	md5hex := getMD5Hash(textData)
	sha256hex := ""

	// benchmark utility which helps obtain number of allocations and bytes allocated per ops.
	b.ReportAllocs()
	// the actual benchmark for PutObject starts here. Reset the benchmark timer.

	for i := 0; b.Loop(); i++ {
		// insert the object.
		objInfo, err := obj.PutObject(b.Context(), bucket, "object"+strconv.Itoa(i),

        // When
        String result = Hexdump.toHexString(data, offset, length);

        // Then
        assertNotNull(result);
        assertFalse(result.isEmpty());
        // Check starts with byte at offset 16 (0x10)
        assertTrue(result.startsWith("10111213"));
        assertEquals(64, result.length()); // 32 bytes * 2 chars per byte
    }

    @Test

	bucketConditionStr := fmt.Sprintf(`["eq", "$bucket", "%s"]`, bucketName)
	// Add the key condition, only accept keys equal to the one passed.
	keyConditionStr := fmt.Sprintf(`["starts-with", "$key", "%s/upload.txt"]`, objectKey)

	// Combine all conditions into one string.
	conditionStr := fmt.Sprintf(`"conditions":[%s, %s]`, bucketConditionStr, keyConditionStr)
	retStr := "{"

 * is by declaring that step to be the last step of the pipeline. Nevertheless, we refer to the
 * "value" of a successful step or the "result" (value or exception) of any step.
 *
 * <ol>
 *   <li>A pipeline starts at its leaf step (or steps), which is created from either a callable
 *       block or a {@link ListenableFuture}.
 *   <li>Each other step is derived from one or more input steps. At each step, zero or more objects