st element in the queue.</p>
<p>Each element of the queue has an associated <a href="dart-collection/DoubleLinkedQueueEntry-class.html">DoubleLinkedQueueEntry</a>.
Returns the entry object corresponding to the first element of the queue.</p>
<p>The entry objects can also be accessed using <a href="dart-collection/DoubleLinkedQueue/lastEntry.html">lastEntry</a>,
and they can be iterated using <a href="dart-collection/DoubleLinkedQueueEntry/nextEntry.html">DoubleLinkedQueueEntry.nextEntry()</a> and
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