Primeiro crie um novo `APIRouter` que conterá um ou mais callbacks.

{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[1,23] *}

### Crie a *operação de rota* do callback { #create-the-callback-path-operation }

Para criar a *operação de rota* do callback, use o mesmo `APIRouter` que você criou acima.

Ela deve parecer exatamente como uma *operação de rota* normal do FastAPI:

func (list *TargetList) Exists(id TargetID) bool {
	list.RLock()
	defer list.RUnlock()

	_, found := list.targets[id]
	return found
}

// TargetIDResult returns result of Remove/Send operation, sets err if
// any for the associated TargetID
type TargetIDResult struct {
	// ID where the remove or send were initiated.
	ID TargetID
	// Stores any error while removing a target or while sending an event.

CAREFUL: When utilizing two-way communication, it is important to ensure that the remote handler is not blocked on a send.
If the remote handler is blocked on a send, and the client is trying to send without the remote receiving,
the operation would become deadlocked if the channels are full.

### Typed handlers

Typed handlers are handlers that have a specific type for the request and response payloads.

```go
    // Create a typed handler.

func (s *xlStorage) ReadAll(ctx context.Context, volume string, path string) (buf []byte, err error) {
	// Specific optimization to avoid re-read from the drives for `format.json`
	// in-case the caller is a network operation.
	if volume == minioMetaBucket && path == formatConfigFile {
		s.RLock()
		formatData := make([]byte, len(s.formatData))
		copy(formatData, s.formatData)
		s.RUnlock()
		if len(formatData) > 0 {

     * @param flags Flags that control the behavior of the operation. When all
     * name associated with SIDs will be required, the SID_FLAG_RESOLVE_SIDS
     * flag should be used which causes all group member SIDs to be resolved
     * together in a single more efficient operation.
     */

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

    //                                               -------
    /**
     * Displays the details of a web authentication configuration.
     *
     * @param crudMode the CRUD mode for the operation
     * @param id the ID of the web authentication to display
     * @return HTML response for the web authentication details page
     */
    @Execute
    @Secured({ ROLE, ROLE + VIEW })

  interface Strategy extends Serializable {

    /**
     * Sets {@code numHashFunctions} bits of the given bit array, by hashing a user element.
     *
     * <p>Returns whether any bits changed as a result of this operation.
     */
    <T extends @Nullable Object> boolean put(
        @ParametricNullness T object,
        Funnel<? super T> funnel,
        int numHashFunctions,
        LockFreeBitArray bits);

    /**

			data[a.Column.Name] = a.Value
		}
		var r T
		return s.c.g.apply(ctx).Model(r).Create(data).Error
	}

	return nil
}

// executeAssociationOperation executes an association operation
func (s setCreateOrUpdateG[T]) executeAssociationOperation(ctx context.Context, op clause.Association) error {
	var r T
	base := s.c.g.apply(ctx).Model(r)

	switch op.Type {
	case clause.OpCreate:

            assertEquals(DcerpcConstants.RPC_C_PF_BROADCAST, message.getFlags());
        }

        @Test
        @DisplayName("getOpnum should return correct operation number")
        void testGetOpnum() {
            assertEquals(10, message.getOpnum()); // TestDcerpcMessage was created with opnum 10
        }
    }