w()
			<-limit
		}(w)
	}
	select{}
}
</pre>

<h3 id="locks">Locks</h3>

<p>
The <code>sync</code> package implements two lock data types,
<code>sync.Mutex</code> and <code>sync.RWMutex</code>.
</p>

<p class="rule">
For any <code>sync.Mutex</code> or <code>sync.RWMutex</code> variable <code>l</code> and <i>n</i> &lt; <i>m</i>,

    </p>

    <p><!-- https://go.dev/issue/57071 -->
      <code>/sync/mutex/wait/total:seconds</code> now includes contention on
      runtime-internal locks in addition to
      <a href="/pkg/sync#Mutex"><code>sync.Mutex</code></a> and
      <a href="/pkg/sync#RWMutex"><code>sync.RWMutex</code></a>.
    </p>
  </dd>
</dl><!-- runtime/metrics -->