Performance regression on 0.20 vulkan

[guusw]

Hey, I recently tried upgrading from 0.19.1 to 0.20 and noticed I get half the performance using vulkan as I did previously.

I did some profiling and noticed all application code is the same except for one vkQueueSubmit taking up 11ms I suspect something is waiting for an operation to complete which did not happen previously.

It's worth nothing that I perform a readback from a texture, although it happens asynchronously using wgpuBufferMapAsync.

Below I have provided two renderdoc captures (before/after the upgrade) The rendered items are identical, the only difference I could notice is some fences at the start of the 0.19 capture

Let me know if I can provide any other information to help.

renderdoc.7z.zip