* Initial implementation of migration between memory heaps - Missing OOM handling - Missing `_map` data safety when remapping - Copy may not have completed yet (needs some kind of fence) - Map may be unmapped before it is done being used. (needs scoped access) - SSBO accesses are all "writes" - maybe pass info in another way. - Missing keeping map type when resizing buffers (should this be done?) * Ensure migrated data is in place before flushing. * Fix issue where old waitable would be signalled. - There is a real issue where existing Auto<> references need to be replaced. * Swap bound Auto<> instances when swapping buffer backing * Fix conversion buffers * Don't try move buffers if the host has shared memory. * Make GPU methods return PinnedSpan with scope * Storage Hint * Fix stupidity * Fix rebase * Tweak rules Attempt to sidestep BOTW slowdown * Remove line * Migrate only when command buffers flush * Change backing swap log to debug * Address some feedback * Disallow backing swap when the flush lock is held by the current thread * Make PinnedSpan from ReadOnlySpan explicitly unsafe * Fix some small issues - Index buffer swap fixed - Allocate DeviceLocal buffers using a separate block list to images. * Remove alternative flags * Address feedback