7ce2a60a1d
Windows 11 support for DISCARD swap effect seems to be buggy and slow. Use FLIP_DISCARD instead. Staying with DISCARD on Windows 10 because of reports of flickering that hopefully won't happen on Windows 11. We're also not using ALLOW_TEARING because it seems to break after an OBS cycle of minimize/restore on both Windows 10 and 11. The swap chain displays a stale image. Not sure if ALLOW_TEARING would be beneficial even if it was working.