synchronous
            waits that were cancelled. If it returns 0 then you were too late and
            the wait handler has already been executed, or will soon be executed.
            If it returns 1 then the wait handler was successfully cancelled.
          </li>
<li class="listitem">
            If a wait handler is cancelled, the boost::system::error_code passed
            to it contains the value <code class="computeroutput">boost::asio::error::operation_aborted</code>.
          </li>
</ul></div>