"identifier">net</span><span class="special">::</span><span class="identifier">async_read_until</span><span class="special">(</span><span class="identifier">stream</span><span class="special">,</span> <span class="identifier">net</span><span class="special">::</span><span class="identifier">dynamic_buffer</span><span class="special">(</span><span class="identifier">s1</span><span class="special">),</span> <span class="char">'\n'</span><span class="special">,</span> <span class="identifier">handler</span><sp