Iterator<String> iterator = list.iterator();
    assertTrue(iterator.hasNext());
    assertEquals("1", iterator.next());
    assertTrue(iterator.hasNext());
    assertEquals("2", iterator.next());
    assertTrue(iterator.hasNext());
    assertEquals("3", iterator.next());
    assertTrue(iterator.hasNext());
    assertEquals("4", iterator.next());
    assertFalse(iterator.hasNext());

    Iterator<String> iterator = skip(list, 2).iterator();
    assertThrows(IllegalStateException.class, () -> iterator.remove());
  }

  public void testSkip_allOfImmutableList_modifiable() {
    List<String> list = ImmutableList.of("a", "b");
    Iterator<String> iterator = skip(list, 2).iterator();
    assertThrows(UnsupportedOperationException.class, () -> iterator.remove());
  }

    /**
     * SAMR CloseHandle operation for closing an opened SAM handle.
     * This operation releases resources associated with the handle.
     */
    public static class SamrCloseHandle extends DcerpcMessage {

        @Override
        public int getOpnum() {
            return 0x01;
        }

        /** The return value of the operation */
        public int retval;

    /**
     * SAMR CloseHandle operation for closing an opened SAM handle.
     * This operation releases resources associated with the handle.
     */
    public static class SamrCloseHandle extends DcerpcMessage {

        @Override
        public int getOpnum() {
            return 0x01;
        }

        /** The return value of the operation */
        public int retval;

... das liegt daran, dass der Client-Generator für jede *Pfadoperation* die OpenAPI-interne **Operation-ID** verwendet.

OpenAPI erfordert, dass jede Operation-ID innerhalb aller *Pfadoperationen* eindeutig ist. Daher verwendet FastAPI den **Funktionsnamen**, den **Pfad** und die **HTTP-Methode/-Operation**, um diese Operation-ID zu generieren. Denn so kann sichergestellt werden, dass die Operation-IDs eindeutig sind.

{* ../../docs_src/openapi_callbacks/tutorial001.py hl[3,25] *}

### Create the callback *path operation* { #create-the-callback-path-operation }

To create the callback *path operation* use the same `APIRouter` you created above.

It should look just like a normal FastAPI *path operation*:

* It should probably have a declaration of the body it should receive, e.g. `body: InvoiceEvent`.

{* ../../docs_src/openapi_callbacks/tutorial001.py hl[3,25] *}

### Crear la *path operation* del callback

Para crear la *path operation* del callback utiliza el mismo `APIRouter` que creaste anteriormente.

Debería verse como una *path operation* normal de FastAPI:

* Probablemente debería tener una declaración del body que debería recibir, por ejemplo `body: InvoiceEvent`.

    }

    /**
     * Add a pending operation
     *
     * @param operation operation to add
     */
    public void addPendingOperation(CommonServerMessageBlock operation) {
        pendingOperations.add(operation);
    }

    /**
     * Remove a pending operation
     *
     * @param operation operation to remove
     * @return true if operation was removed
     */

```

...eso es porque el generador del cliente usa el **operation ID** interno de OpenAPI para cada *path operation*.

OpenAPI requiere que cada operation ID sea único a través de todas las *path operations*, por lo que FastAPI usa el **nombre de la función**, el **path**, y el **método/operación HTTP** para generar ese operation ID, porque de esa manera puede asegurarse de que los operation IDs sean únicos.

import java.util.Collections;
import java.util.Iterator;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * A utility for testing an Iterator implementation by comparing its behavior to that of a "known
 * good" reference implementation. In order to accomplish this, it's important to test a great
 * variety of sequences of the {@link Iterator#next}, {@link Iterator#hasNext} and {@link