HRESULT XGameStreamingGetStreamPhysicalDimensions(
         XGameStreamingClientId client,
         uint32_t* horizontalMm,
         uint32_t* verticalMm
)

void GetSmallestStreamingClient(uint32_t& widthMm, uint32_t& heightMm)
    {
        // If we don't know what the smallest client is, then search through them to find it
        if (m_smallestClient == XGameStreamingNullClientId)
        {
            for (const auto client : m_streamingClients)
            {
                if (client.clientId != XGameStreamingNullClientId)
                {
                    uint32_t clientWidthMm = 0;
                    uint32_t clientHeightMm = 0;
                    if (SUCCEEDED(XGameStreamingGetStreamPhysicalDimensions(client.clientId, &clientWidthMm, &clientHeightMm)))
                    {
                        if (clientWidthMm < m_smallestClientWidthMm)
                        {
                            m_smallestClientWidthMm = clientWidthMm;
                            m_smallestClientHeightMm = clientHeightMm;
                        }
                    }
                }
            }
        }

        widthMm = m_smallestClientWidthMm;
        heightMm = m_smallestClientHeightMm;
    }