nternally the method cancels its subscription after these elements. This
means that single-subscription (non-broadcast) streams are closed and
cannot be reused after a call to this method.</p>
<p>If an error event occurs before the value is found, the future completes
with this error.</p>
<p>If a done event occurs before the value is found, the future completes
with a <a href="dart-core/RangeError-class.html">RangeError</a>.</p>
    </section>
    
    <section class="summary source-code" id="source">
     