n class="parameter" id="onCancel-param-subscription"><span class="type-annotation"><a href="dart-async/StreamSubscription-class.html">StreamSubscription</a><span class="signature">&lt;<wbr><span class="type-parameter">T</span>&gt;</span></span> <span class="parameter-name">subscription</span></span>)</span> })
            <span class="returntype parameter">&#8594; <a href="dart-async/Stream-class.html">Stream</a><span class="signature">&lt;<wbr><span class="type-parameter"><a href="dart-io/RawSocketEvent-cl