ass="emphasis"><em>asymmetric_coroutine&lt;&gt;::push_type</em></span>
        does not pass the control of execution to <span class="emphasis"><em>coroutine-function</em></span>
        - instead the first call of <span class="emphasis"><em>asymmetric_coroutine&lt;&gt;::push_type::operator()</em></span>
        synthesizes a complementary <span class="emphasis"><em>asymmetric_coroutine&lt;&gt;::pull_type</em></span>
        and passes it as reference to <span class="emphasis"><em>coroutine-function</em></s