 stream manipulator instance
            (see <a href="http://www.cppreference.com/wiki/io/io_flags#manipulators" target="_top">Manipulators</a>),
            which when streamed to an output stream will result in generating the
            output as emitted by the embedded <span class="emphasis"><em>Spirit.Karma</em></span> generator
            expression. Any error occurring during the invocation of the <span class="emphasis"><em>Spirit.Karma</em></span>
            generators will be reflected in the st