fix: Change UnityVulkanPluginEventConfig parameters for vulkan API

[karasusan]

This PR fixes the performance issue of video streaming when using vulkan graphics API on Linux with Unity 2022.2.

This issue is able to replicated by this condition below.

• Ubuntu 20.04
• Unity 2022.2 (Unity 2022.1 works fine)
• Use the samples of Unity Render Streaming
• Stream a video from Broadcast sample and receive a video streaming on Browser
• Any video codecs
• Build runtime (Not reproduced the issue on Unity Editor)
• Vulkan graphics API

The cause of this issue is handling errors occurred by vulkan synchronization between GPU and CPU. In addition, The timing of accessing rendering queue is another reason. We fixed the timing with callback of UnityVulkanInterface::AccessQueue.

[karasusan]

When I run Unity Render Streaming with this change, it freezes on Ubuntu 20.04.

[BrianHarrisonUnity]

I believe we will need to include a fix from. #888 PR that resolves an infinite hang when calling ResetSync.

I made a branch with this change called vulkan-commandbuffer-experimental-fix that is working for me now on Ubuntu 20.04 when testing with the package samples.

[karasusan]

@BrianHarrisonUnity I merged your fix into this branch. Thank you.

[BrianHarrisonUnity]

Greetings @karasusan!

After testing around with this branch, I found a crashing issue occuring infrequently. I tracked down the issue, and it was happening due to calling the AccessTexture API during the OnRenderEvent with the event configured for exclusive queue access. The AccessTexture API cannot happen during events with exclusive queue access.

To resolve this issue, I created a new branch called, experimental/vulkan-queue-access-submit. I think this branch resolves the remaining issues. Also, since it no longer requires flushing the command buffer prior to the OnRenderEvent, I think the performance should be better as well!

[karasusan]

@BrianHarrisonUnity I checked the new branch experimental/vulkan-queue-access-submit.

PeerConnection sample in WebRTC package works well with this fix. However, when checking Broadcast sample in Unity Render Streaming package, I found video streaming stops for a while. We can see the issue in this video from 30 sec. Please pay attention to the mouse position in the video.

https://user-images.githubusercontent.com/1132081/229075158-cc7c531c-f4f4-42dc-839a-fe7f18a2d6a4.mp4

[BrianHarrisonUnity]

@karasusan I think I have seen the stream hiccup before, even on an old version of Unity & the package. In my case, it seemed to only happen if my machine was resource starved, and the client was unable to keep up temporarily. From the video, it looks like the sender is still running in the background, and it was only on the client side that the stream hiccuped.

Do you consistently see that issue, and if you try in release, or on a standalone build, does it still happen? Also, if you run it again, could you check what the WebRTC stats are showing when that happens?