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.