Method ReusableStringStream

unittests/catch.hpp:9536–9539

    }

    ReusableStringStream::ReusableStringStream()
    :   m_index( StringStreams::instance().add() ),
        m_oss( StringStreams::instance().m_streams[m_index].get() )
    {}

    ReusableStringStream::~ReusableStringStream() {
        static_cast<std::ostringstream*>( m_oss )->str("");