Method DebugOutStream

extras/catch_amalgamated.cpp:4645–4648

            std::ostream m_os;
        public:
            DebugOutStream()
            :   m_streamBuf( Detail::make_unique<StreamBufImpl<OutputDebugWriter>>() ),
                m_os( m_streamBuf.get() )
            {}

        public: // IStream
            std::ostream& stream() override { return m_os; }