*       java.util.function.Function} is accepted (for example {@link java.util.stream.Stream#map
 *       Stream.map}).
 *   <li><b>Do not</b> call {@link #doForward} or {@link #doBackward} directly; these exist only to
 *       be overridden.
 * </ul>
 *
 * <h3>Example</h3>
 *
 * {@snippet :
 * return Converter.from(
 *     Integer::toHexString,
 *     s -> parseUnsignedInt(s, 16));
 * }
 *

# Async Tests { #async-tests }

You have already seen how to test your **FastAPI** applications using the provided `TestClient`. Up to now, you have only seen how to write synchronous tests, without using `async` functions.

    extends AggregateFutureState<OutputT> {
  private static final LazyLogger logger = new LazyLogger(AggregateFuture.class);

  /**
   * The input futures. After {@link #init}, this field is read only by {@link #afterDone()} (to
   * propagate cancellation) and {@link #toString()}. To access the futures' <i>values</i>, {@code
   * AggregateFuture} attaches listeners that hold references to one or more inputs. And in the case

### Creating the `Settings` only once with `lru_cache` { #creating-the-settings-only-once-with-lru-cache }

Reading a file from disk is normally a costly (slow) operation, so you probably want to do it only once and then reuse the same settings object, instead of reading it for each request.

But every time we do:

```Python

 *
 * @author George van den Driessche
 * @author Chris Povirk
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")

      assertEquals(ImmutableMap.of(5, 'x'), row);
    }
  }

  @SuppressWarnings("unchecked") // C can only be @Nullable Character or Character
  protected @NonNull C cellValue(Character character) {
    return (C) character;
  }

  // Only safe wrt. ClassCastException. Not null-safe (can be used to test expected Table NPEs)
  @SuppressWarnings("unchecked")

     * system properties collected so far, along with other information. This method should return altered
     * (contributions applied) user properties, not only the "new" or "added" properties!
     *
     * @param protoSession The proto session, never {@code null}.
     * @return The user properties with contributions.
     */

     * another goal of the same plugin.
     * @return the goal
     */
    @Nonnull
    String goal() default "";

    /**
     * Lifecycle id of the lifecycle that defines {@link #phase()}. Only valid in combination with {@link #phase()}. If
     * not specified, Maven will use the lifecycle of the current build.
     *

MinIO is built ground up on the cloud-native premise. With features like erasure-coding, distributed and shared setup, it focuses only on storage and does it very well. While, it can be scaled by just replicating MinIO instances per tenant via an orchestration platform.

<img src="/img/tutorial/request-form-models/image01.png">
</div>

## Forbid Extra Form Fields { #forbid-extra-form-fields }

In some special use cases (probably not very common), you might want to **restrict** the form fields to only those declared in the Pydantic model. And **forbid** any **extra** fields.

/// note

This is supported since FastAPI version `0.114.0`. 🤓

///