Allow access to full LoaderContext in load and transform hooks for webpack/rspack

[urbnjamesmi1]

Describe the feature

I am currently trying to migrate a custom webpack loader to unplugin. The webpack unplugin needs access to the loader context's request property in the transform hook. The id parameter is just the loader context's resource property.

It would be advantageous to be able to access the build-system's native loader context (if available) from the load and transform hooks. This would make it easier to convert custom loaders to unplugin.

Additional information

• [X] Would you be willing to help implement this feature?