/Iterable/contains.html">Iterable.contains</a> operations, and it should catch concurrent modifications
of the keys while iterating.</p>
<p>A more efficient implementation is usually possible by overriding
some of the other members as well.</p>
    </section>
    
    <section>
      <dl class="dl-horizontal">

        <dt>Implements</dt>
        <dd>
          <ul class="comma-separated clazz-relationships">
            <li><a href="dart-core/Map-class.html">Map</a><span class="signature">&lt;K, V&gt;</spa