* Most Multimap implementations use a List or Set (or even Multiset) for their values, in which
     * case Multimap equality works as expected. Users who use a Collection type that does not
     * implement equals(), such as most Queue implementations, will get the same behavior from our
     * value-collection wrappers (and from Multimap.equals) as from the underlying Collection.
     */
    @SuppressWarnings("UndefinedEquals")

  Now, when unschedulable Pods are updated, the scheduling queue checks with QueueingHint(s) whether the update may make the pods schedulable, and requeues them to activeQ/backoffQ **only when** at least one QueueingHint(s) return Queue. 
  
  Action required for custom scheduler plugin developers:

			}
			t.Log("Client Context canceled. err state:", err)
			clientCanceled <- time.Now()
		}(t)
		start := time.Now()
		if st.Requests != nil {
			defer close(st.Requests)
		}
		// Fill up queue.
		for sendReq {
			select {
			case st.Requests <- []byte("Hello"):
				time.Sleep(10 * time.Millisecond)
			default:
				sendReq = false
			}
		}
		cancel()
		<-serverCanceled

     * Most Multimap implementations use a List or Set (or even Multiset) for their values, in which
     * case Multimap equality works as expected. Users who use a Collection type that does not
     * implement equals(), such as most Queue implementations, will get the same behavior from our
     * value-collection wrappers (and from Multimap.equals) as from the underlying Collection.
     */
    @SuppressWarnings("UndefinedEquals")

- Sometimes, the scheduler incorrectly placed a pod in the "unschedulable" queue instead of the "backoff" queue. This happened when some plugin previously declared the pod as "unschedulable" and then in a later attempt encounters some other error. Scheduling of that pod then got delayed by up to five minutes, after which periodic flushing moved the pod back into the "active" queue. ([#120334](https://github.com/kubernetes/kubernetes/pull/120334), [@pohly](https://github.com/pohly))...

github.com/eapache/go-xerial-snappy v0.0.0-20230731223053-c322873962e3/go.mod h1:YvSRo5mw33fLEx1+DlK6L2VV43tJt5Eyel9n9XBcR+0=
github.com/eapache/queue v1.1.0 h1:YOEu7KNc61ntiQlcEeUIoDTJ2o8mQznoNvUhiigpIqc=
github.com/eapache/queue v1.1.0/go.mod h1:6eCeP0CKFpHLu8blIFXhExK/dRa7WDZfr6jVFPTqq+I=
github.com/eclipse/paho.mqtt.golang v1.5.0 h1:EH+bUVJNgttidWFkLLVKaQPGmkTUfQQqjOsyvMGvD6o=

- Fixes the bug in PodTopologySpread that only happens with QHint enabled, 

- Previously, the scheduling queue didn't notice any extenders' failures, potentially resulting in missed cluster events and Pods rejected by Extenders being stuck in the unschedulable pod pool for up to 5 minutes in the worst-case scenario. Now, the scheduling queue notices extenders' failures and requeues Pods rejected by Extenders appropriately.

- Sometimes, the scheduler incorrectly placed a pod in the "unschedulable" queue instead of the "backoff" queue. This happened when some plugin previously declared the pod as "unschedulable" and then in a later attempt encounters some other error. Scheduling of that pod then got delayed by up to five minutes, after which periodic flushing moved the pod back into the "active" queue. ([#120334](https://github.com/kubernetes/kubernetes/pull/120334), [@pohly](https://github.com/pohly))...

import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.Nullable;

/**
 * Static utility methods pertaining to {@link Set} instances. Also see this class's counterparts
 * {@link Lists}, {@link Maps} and {@link Queues}.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/CollectionUtilitiesExplained#sets">{@code Sets}</a>.
 *
 * @author Kevin Bourrillion
 * @author Jared Levy