/*
     * In principle, a Multimap implementation could add e3 first before failing on the null. But
     * that seems unlikely enough to be worth complicating the test over, especially if there's any
     * chance that a permissive test could mask a bug.
     */
    expectUnchanged();
    // Be extra thorough in case internal state was corrupted by the expected null.

 * such custom interfaces directly; they are implemented only in subclasses. Therefore, forwarding
 * {@code equals} would break symmetry, as the forwarding object might consider itself equal to the
 * object being tested, but the reverse could not be true. This behavior is consistent with the
 * JDK's collection wrappers, such as {@link java.util.Collections#unmodifiableCollection}. Use an

     * won't be cleared as long as the enum constant is referenced somewhere, and the enum constant
     * is referenced somewhere for as long as the enum class is loaded. *Maybe in theory* the enum
     * class could be unloaded after the above call to `getEnumConstants` but before we call
     * `get()`, but that is vanishingly unlikely.
     */
    return ref == null ? Optional.absent() : Optional.fromNullable(enumClass.cast(ref.get()));
  }

And then you can set headers in that *temporal* response object.

{* ../../docs_src/response_headers/tutorial002.py hl[1, 7:8] *}

And then you can return any object you need, as you normally would (a `dict`, a database model, etc).

And if you declared a `response_model`, it will still be used to filter and convert the object you returned.

  // TODO(b/418181860): This method creates retain cycles in J2ObjC. In order to break the cycle,
  // there needs to be separate classes for primary and descending multiset, where the primary one
  // would hold {@code @LazyInit @RetainedWith @Nullable} reference to its descending multiset, and
  // the other {@code final} reference.
  @Override
  public SortedMultiset<E> descendingMultiset() {

import org.jspecify.annotations.Nullable;

/**
 * A class that can supply objects of a single type; a pre-Java-8 version of {@link
 * java.util.function.Supplier java.util.function.Supplier}. Semantically, this could be a factory,
 * generator, builder, closure, or something else entirely. No guarantees are implied by this
 * interface.
 *
 * <p>The {@link Suppliers} class provides common suppliers and related utilities.
 *

### In production { #in-production }

In your production system, you probably have a frontend created with a modern framework like React, Vue.js or Angular.

And to communicate using WebSockets with your backend you would probably use your frontend's utilities.

Or you might have a native mobile application that communicates with your WebSocket backend directly, in native code.

 * the beginning, thanks to using different `-source -target` values for compiling our `-jre` and
 * `-android` "flavors.")
 *
 * (We could consider releasing a listenablefuture:1.0.1 someday. But we would want to look into how
 * that affects users, especially users of the Android Gradle Plugin, since the plugin developers
 * put in a special hack for us: https://issuetracker.google.com/issues/131431257)
 */

 * the beginning, thanks to using different `-source -target` values for compiling our `-jre` and
 * `-android` "flavors.")
 *
 * (We could consider releasing a listenablefuture:1.0.1 someday. But we would want to look into how
 * that affects users, especially users of the Android Gradle Plugin, since the plugin developers
 * put in a special hack for us: https://issuetracker.google.com/issues/131431257)
 */

      val toVerify = result[result.size - 1] as X509Certificate

      // If this cert has been signed by a trusted cert, use that. Add the trusted certificate to
      // the end of the chain unless it's already present. (That would happen if the first
      // certificate in the chain is itself a self-signed and trusted CA certificate.)
      val trustedCert = trustRootIndex.findByIssuerAndSignature(toVerify)
      if (trustedCert != null) {