* query than the original; your mileage may vary. Precomputation takes time and requires more
   * memory, so it is only likely to be worthwhile if the precomputed matcher is queried very often.
   *
   * <p>This method has no effect (returns {@code this}) when called in GWT: it's unclear whether a
   * precomputed matcher is faster, but it certainly would consume more memory (which doesn't seem

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

  - apiserver_flowcontrol_current_r: R(the time of the last change in state of the queues)
  - apiserver_flowcontrol_dispatch_r: R(the time of the latest request dispatch)
  - apiserver_flowcontrol_latest_s: S(the request last dispatched) = R(when that request starts executing in the virtual world)
  - apiserver_flowcontrol_next_s_bounds: min and max next S among non-empty queues

### **Instrumentation**

#### **Audit**

*   Adjust batching audit webhook default parameters: increase queue size, batch size, and initial backoff. Add throttling to the batching audit webhook. Default rate limit is 10 QPS. ([#53417](https://github.com/kubernetes/kubernetes/pull/53417),[ @crassirostris](https://github.com/crassirostris))

- Fixed a panic in `kubectl exec` when the terminal size queue delegate is uninitialized. ([#136280](https://github.com/kubernetes/kubernetes/pull/136280), [@seekskyworld](https://github.com/seekskyworld)) [SIG CLI]

- Added `SchedulerPopFromBackoffQ` feature gate that is in beta and enabled by default. Improved scheduling queue behavior by popping pods from the backoffQ when the activeQ is empty. This allows to process potentially schedulable pods ASAP, eliminating a penalty effect of the backoff queue. ([#130772](https://github.com/kubernetes/kubernetes/pull/130772), [@macsko](https://github.com/macsko)) [SIG Scheduling and Testing]

    - `scheduler_async_api_call_duration_seconds`: histogram of API call execution duration by call type and result
    - `scheduler_pending_async_api_calls`: gauge showing current number of pending API calls in the queue. ([#133120](https://github.com/kubernetes/kubernetes/pull/133120), [@utam0k](https://github.com/utam0k)) [SIG Release and Scheduling]

### Scheduling

- Improved fairness of the scheduling queue by placing pods which are attempted recently behind other pods with the same priority. ([#73700](https://github.com/kubernetes/kubernetes/pull/73700), [@denkensk](https://github.com/denkensk))

* Change default value of deleting-pods-burst to 1 ([#27606](https://github.com/kubernetes/kubernetes/pull/27606), [@gmarek](https://github.com/gmarek))
* MESOS: fix race condition in contrib/mesos/pkg/queue/delay ([#24916](https://github.com/kubernetes/kubernetes/pull/24916), [@jdef](https://github.com/jdef))

	Maintenance    bool
	DeploymentType string
	NoLogging      bool
}

// HealthResult returns the current state of the system, also
// additionally with any specific heuristic information which
// was queried
type HealthResult struct {
	Healthy       bool
	HealthyRead   bool
	HealingDrives int
	ESHealth      []struct {
		Maintenance   bool
		PoolID, SetID int
		Healthy       bool