boost</span><span class="special">::</span><span class="identifier">fibers</span><span class="special">::</span><span class="identifier">buffered_channel</span><span class="special">&lt;</span> <span class="identifier">future_t</span> <span class="special">&gt;</span> <span class="special">&gt;</span> <span class="identifier">chan</span><span class="special">(</span>
            <span class="identifier">wait_all_until_error_source</span><span class="special">(</span> <span class="identifier">std</span><span