may be considered to be able to return false
even when the mutex <i>l</i> is unlocked.
</p>

<h3 id="once">Once</h3>

<p>
The <code>sync</code> package provides a safe mechanism for
initialization in the presence of multiple goroutines
through the use of the <code>Once</code> type.
Multiple threads can execute <code>once.Do(f)</code> for a particular <code>f</code>,
but only one will run <code>f()</code>, and the other calls block

### Feature

- API request throttling (due to a high rate of requests) is now reported in client-go logs at log level 2.  The messages are of the form:`Throttling request took 1.50705208s, request: GET:<URL>` The presence of these messages may indicate to the administrator the need to tune the cluster accordingly. ([#87740](https://github.com/kubernetes/kubernetes/pull/87740), [@jennybuckley](https://github.com/jennybuckley)) [SIG API Machinery]

         * pending, so its `state` field hasn't been nulled out yet.
         *
         * OK, it's technically possible for this to fail in the presence of unsafe publishing, as
         * discussed in the comments in TimeoutFuture. TODO(cpovirk): Maybe check for null before
         * calling recordOutputCancellation?
         */

			r, size = utf8.DecodeLastRune(s[0:i])
		}
		i -= size
		if f(r) == truth {
			return i
		}
	}
	return -1
}

// asciiSet is a 32-byte value, where each bit represents the presence of a
// given ASCII character in the set. The 128-bits of the lower 16 bytes,
// starting with the least-significant bit of the lowest word to the
// most-significant bit of the highest word, map to the full range of all

    authentication credentials before creating TLS tunnels through HTTP proxies (HTTP `CONNECT`).
    Authenticators should identify preemptive authentications by the presence of a challenge whose
    scheme is "OkHttp-Preemptive".

 *  **OkHttp now offers full-operation timeouts.** This sets a limit on how long the entire call may

	#line 1 "not-str-lit"
	void __cgo_f_1_5(void) { static const char __cgo_undefined__5[] = (foo); }

This program will not compile, but cgo can use the presence or absence
of an error message on a given line to deduce the information it
needs. The program is syntactically valid regardless of whether each
name is a type or an ordinary identifier, so there will be no syntax

* AWS: recognize us-east-2 region ([#35013](https://github.com/kubernetes/kubernetes/pull/35013), [@justinsb](https://github.com/justinsb))
* Replace controller presence checking logic ([#36924](https://github.com/kubernetes/kubernetes/pull/36924), [@krousey](https://github.com/krousey))

`PodDisruptionBudget` objects), then **BEFORE**  upgrading from 1.4 to 1.5, you must delete all `PodDisruptionBudget` objects (`policy/v1alpha1/PodDisruptionBudget`) that you have created. It is not possible to delete these objects after you upgrade, and their presence will prevent you from using the beta PodDisruptionBudget feature in 1.5 (which uses `policy/v1beta1/PodDisruptionBudget`). If you have already upgraded, you will need to downgrade the master to 1.4 to delete the `policy/v1alpha1/PodDisruptionBudget`...

- The metadata.clusterName field is deprecated. This field has always been unwritable and always blank, but its presence is confusing, so we will remove it next release. Out of an abundance of caution, this release we have merely changed the name in the go struct to ensure any accidental client uses are found before complete removal. ([#108717](https://github.com/...

- Fixed a bug that prevents the use of ephemeral containers in the presence of a validating admission webhook. ([#94685](https://github.com/kubernetes/kubernetes/pull/94685), [@verb](https://github.com/verb)) [SIG Node and Testing]