Method DebugOutStream

deps/Catch/catch.hpp:13626–13629

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

            ~DebugOutStream() override = default;