*
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingExecutorService}.
 *
 * @author Kurt Alfred Kluever
 * @since 10.0
 */
@J2ktIncompatible
@GwtIncompatible

 * FutureTask#done() done()} method. For similar functionality, call {@link #addListener}.
 *
 * <p>Few users should use this class. It is intended primarily for those who are implementing an
 * {@code ExecutorService}. Most users should call {@link ListeningExecutorService#submit(Callable)
 * ListeningExecutorService.submit} on a service obtained from {@link
 * MoreExecutors#listeningDecorator}.

  /**
   * Generates a number in [0, 2^numBits) with an exponential distribution. The floor of the log2 of
   * the absolute value of the result is chosen uniformly at random in [0, numBits), and then the
   * result is chosen from those possibilities uniformly at random.
   *
   * <p>Zero is treated as having log2 == 0.
   */
  static double randomDouble(int maxExponent) {
    double result = RANDOM_SOURCE.nextDouble();

      throw AssertionError("failed to get ALPN selected protocol", e)
    }
  }

  /**
   * Handle the methods of ALPN's ClientProvider and ServerProvider without a compile-time
   * dependency on those interfaces.
   */
  private class AlpnProvider(
    /** This peer's supported protocols. */
    private val protocols: List<String>,
  ) : InvocationHandler {
    /** Set when remote peer notifies ALPN is unsupported. */

        this.collectionFilter = filter;

        return this;
    }

    /**
     * Gets the artifact filter that controls downloading of artifact files. This filter operates on those artifacts
     * that have been included by the {@link #getCollectionFilter()}.
     *
     * @return The filter used to determine which of the artifacts should have their files resolved or {@code null} to

/**
 * {@link TestCase} for {@link HostSpecifier}. This is a relatively cursory test, as HostSpecifier
 * is a thin wrapper around {@link InetAddresses} and {@link InternetDomainName}; the unit tests for
 * those classes explore numerous corner cases. The intent here is to confirm that everything is
 * wired up properly.
 *
 * @author Craig Berry
 */
@NullUnmarked
public final class HostSpecifierTest extends TestCase {

It's also possible to declare the list as `"*"` (a "wildcard") to say that all are allowed.

But that will only allow certain types of communication, excluding everything that involves credentials: Cookies, Authorization headers like those used with Bearer Tokens, etc.

So, for everything to work correctly, it's better to specify explicitly the allowed origins.

## Use `CORSMiddleware` { #use-corsmiddleware }

   * cartesian product is constructed, the input lists are merely copied. Only as the resulting list
   * is iterated are the individual lists created, and these are not retained after iteration.
   *
   * @param lists the lists to choose elements from, in the order that the elements chosen from
   *     those lists should appear in the resulting lists
   * @param <B> any common base class shared by all axes (often just {@link Object})

In many cases you might already know the answer for those questions. 🤓

If you are helping a lot of people with their questions, you will become an official [FastAPI Expert](fastapi-people.md#fastapi-experts){.internal-link target=_blank}. 🎉

A `Request` also has a `request.receive`, that's a function to "receive" the body of the request.

The `scope` `dict` and `receive` function are both part of the ASGI specification.

And those two things, `scope` and `receive`, are what is needed to create a new `Request` instance.