y and passed as reference to <span class="emphasis"><em>coroutine-function</em></span>.
      </p>
<p>
        This kind of coroutine provides <span class="emphasis"><em>asymmetric_coroutine&lt;&gt;::pull_type::operator()</em></span>.
        This method only switches context; it transfers no data.
      </p>
<p>
        <span class="emphasis"><em>asymmetric_coroutine&lt;&gt;::pull_type</em></span> provides input
        iterators (<span class="emphasis"><em>asymmetric_coroutine&lt;&gt;::pull_type::iterator