><span class="p">(</span><span class="n">error_code</span><span class="p">,</span> <span class="n">T</span><span class="p">)</span><span class="o">&gt;</span>                   <span class="c1">//
</span><span class="c1"></span>
    <span class="c1">// NOTE we subclass for an async result taking an outcome::result
</span><span class="c1"></span>    <span class="c1">// as its completion handler. We will mangle the void(error_code, T)
</span><span class="c1"></span>    <span class="c1">// completion handler i