add into_custom api for Instance Queue, and Device

[mikialex]

Connections

related issue: #7714 and specific discussion: #7714 (comment)

Description

This PR adds util methods to convert some wgpu-level api into its internal custom one. Currently, only for Instance, Queue and Device, as these are the most common places to inject custom logic.

Testing

The change is simple to verify.

Checklist

• Run cargo fmt.
• Run taplo format.
• Run cargo clippy --tests. If applicable, add:
  • --target wasm32-unknown-unknown
• Run cargo xtask test to run tests.
• If this contains user-facing changes, add a CHANGELOG.md entry.

[nical]

The motivations you presented for this are already covered by a different API. You should extend the internal counters if you are missing information.

[sagudev]

The motivations you presented for this are already covered by a different API. You should extend the internal counters if you are missing information.

Actually I can see how something like this could be useful for someone that wants to create wrapper (custom backend) for wgpu types, but does not need to wrap/override all, just some of them. The question is whether we are willing to offer them this shortcut.

[cwfitzgerald]

@nical could you follow up on this?

[nical]

I am very sorry for the delay. For now we want to be cautious about how much we expose and how much API surface we add, so we decided to not add this.
If you want to create a custom device you'll have to make a custom wrapper backend that wraps all objects as sagudev suggested.