 class="keyword">class</span> <span class="identifier">AsyncReadStream</span><span class="special">&gt;</span>
<span class="keyword">void</span> <span class="identifier">f</span><span class="special">(</span><span class="identifier">AsyncReadStream</span><span class="special">&amp;</span> <span class="identifier">stream</span><span class="special">)</span>
<span class="special">{</span>
    <span class="keyword">static_assert</span><span class="special">(</span><span class="identifier">is_async_read_stream<