We want to see that new features have some significant advantage over the alternatives.
        These advantages can take
        [many forms](https://github.com/google/guava/wiki/PhilosophyExplained#utility), but taking
        the time to discuss them in detail will make it much clearer why this feature should be
        added to Guava.


        Please fill out the following fields to give us a better understanding of your proposed

            boolean defaultsToEmpty);

    /**
     * Creates a composite function from a collection of functions.
     *
     * @param functions A collection of functions, each taking a String as input and returning a String.
     * @return A function that applies each function in the collection in order until a non-null result is found.

     * @param domain The domain in which the user has an account.
     * @param user The username for the authenticating user.
     * @param workstation The workstation from which authentication is
     * taking place.
     */
    /**
     * Creates a Type-3 message in response to the given Type-2 message.
     *
     * @param type2 the Type-2 message to respond to
     * @param password the user's password

                // Don't want to have two workers pulling from the queue.
                return;
              } else {
                // Increment the run counter to avoid the ABA problem of a submitter marking the
                // thread as QUEUED after it already ran and exhausted the queue before returning
                // from execute().
                workerRunCount++;
                workerRunningState = RUNNING;

But at some point, there was no other option than creating something that provided all these features, taking the best ideas from previous tools, and combining them in the best way possible, using language features that weren't even available before (Python 3.6+ type hints).

</blockquote>

## Investigation { #investigation }

import org.jspecify.annotations.Nullable;

/**
 * A listening executor service which forwards all its method calls to another listening executor
 * service. Subclasses should override one or more methods to modify the behavior of the backing
 * executor service as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code

  @Override
  @Nullable V getIfCached(@Nullable Object key) {
    V value = super.getIfCached(key);
    if (value != null) {
      return value;
    }

    // Store a local reference to the cache entry. If the backing map is immutable, this,
    // in combination with immutable cache entries, will ensure a thread-safe cache.
    CacheEntry<K, V> entry;

    // Check cache. We use == on purpose because it's cheaper and a cache miss is ok.

    /**
     * The internal LRU hash map used to store elements.
     */
    private final LruHashMap<E, Object> map;

    // Dummy value to associate with an Object in the backing Map
    private static final Object PRESENT = new Object();

    /**
     * Creates a new {@link LruHashSet} with the specified limit size.
     *
     * @param limitSize

    //    were added to the queue. It's easily possible for one thread to take the head of the
    //    queue, immediately followed by another thread taking the next element in the queue. That
    //    second thread can then dispatch to the subscriber it took before the first thread does.
    //

   <span style="background-color:#007166"><font color="#D3D7CF"> module </font></span>  🐍 main.py

     <span style="background-color:#007166"><font color="#D3D7CF"> code </font></span>  Importing the FastAPI app object from the module with the
             following code: