Let's start with an example and then see it in detail.

We create an async function `lifespan()` with `yield` like this:

{* ../../docs_src/events/tutorial003.py hl[16,19] *}

Here we are simulating the expensive *startup* operation of loading the model by putting the (fake) model function in the dictionary with machine learning models before the `yield`. This code will be executed **before** the application **starts taking requests**, during the *startup*.

		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrAccessDenied), r.URL)
		return
	}

	kmsContext := kms.Context{"MinIO admin API": "KMSKeyStatusHandler"} // Context for a test key operation
	// 1. Generate a new key using the KMS.
	key, err := GlobalKMS.GenerateKey(ctx, &kms.GenerateKeyRequest{Name: keyID, AssociatedData: kmsContext})
	if err != nil {
		response.EncryptionErr = err.Error()

$element.trigger($.Event(EVENT_EXPANDED))\n    }\n  }\n\n  // Static\n\n  static _jQueryInterface(operation) {\n    return this.each(function () {\n      let data = $(this).data(DATA_KEY)\n\n      if (!data) {\n        data = new ExpandableTable($(this))\n        $(this).data(DATA_KEY, data)\n      }\n\n      if (typeof operation === 'string' && /init|toggleRow/.test(operation)) {\n        data[operation]()\n      }\n    })\n  }\n}\n\n/**\n  * Data API\n  * ====================================================\n...

    //                                               -------
    /**
     * Displays the details of a specific failure URL record.
     *
     * @param crudMode the CRUD operation mode (should be DETAILS)
     * @param id the ID of the failure URL record to display
     * @return HTML response for the failure URL details page
     */
    @Execute
    @Secured({ ROLE, ROLE + VIEW })

import okio.ByteString

/**
 * A non-blocking interface to a web socket. Use the [factory][WebSocket.Factory] to create
 * instances; usually this is [OkHttpClient].
 *
 * ## Web Socket Lifecycle
 *
 * Upon normal operation each web socket progresses through a sequence of states:
 *
 *  * **Connecting:** the initial state of each web socket. Messages may be enqueued but they won't
 *    be transmitted until the web socket is open.
 *

// errSignatureMismatch means signature did not match.
var errSignatureMismatch = errors.New("Signature does not match")

// When upload object size is greater than 5G in a single PUT/POST operation.
var errDataTooLarge = errors.New("Object size larger than allowed limit")

// When upload object size is less than what was expected.
var errDataTooSmall = errors.New("Object size smaller than expected")

	// Log unhandled errors.
	if _, ok := err.(BucketPolicyNotFound); !ok {
		internalLogIf(GlobalContext, err, logger.WarningKind)
	}

	// As policy is not available for given bucket name, returns IsOwner i.e.
	// operation is allowed only for owner.
	return args.IsOwner
}

// NewPolicySys - creates new policy system.
func NewPolicySys() *PolicySys {
	return &PolicySys{}
}

/// tip | Dica

Observe que, assim como [dependências em *decoradores de operação de rota*](dependencies/dependencies-in-path-operation-decorators.md){.internal-link target=_blank}, nenhum valor será passado para sua *função de operação de rota*.

///

O resultado final é que os caminhos dos itens agora são:

* `/items/`
* `/items/{item_id}`

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Simplified circuit breaker implementation for SMB operations.
 * Thread-safe and lock-free implementation to prevent cascading failures.
 *
 * Features:
 * - Simple state management (CLOSED, OPEN, HALF_OPEN)
 * - Lock-free atomic operations
 * - Configurable thresholds and timeouts
 * - No complex dependencies
 */
public class SimpleCircuitBreaker {

		t.Errorf("MinIO %s: Failed to create HTTP request for testing the response when object Layer is set to `nil`.", instanceType)
	}
	// execute the object layer set to `nil` test.
	// `ExecObjectLayerAPINilTest` manages the operation.
	ExecObjectLayerAPINilTest(t, nilBucket, nilObject, instanceType, apiRouter, nilReq)
}

func TestAPIHeadObjectHandlerWithEncryption(t *testing.T) {
	globalPolicySys = NewPolicySys()