ays throws exceptions on failure through
its coroutine token transformation. The <a href="https://www.boost.org/doc/libs/develop/doc/html/boost_asio/reference/experimental__redirect_error.html"><code>redirect_error</code></a>
token transformation recovers the option to use the <code>error_code</code> interface,
but it suffers from the <a href="../motivation/error_codes.html">same drawbacks</a>
that make pure error codes unappealing in the synchronous case.</p>

<p>This recipe fixes that by making it possibl