Prepend label to field names used with `#[instrument]`

[mdtusz]

Feature Request

Add the ability to prepend a string scope to field labels when using the #[instrument] attribute macro.

Motivation

When using the #[instrument] macro on functions, the field names are taken verbatim from the argument names, so common or short names can become difficult to identify among other fields included in a trace, e.g. a function that uses id, name, or target as argument names. Having the option to prepend a field label to the argument names will allow for easier search and identification, and a way to avoid conflicts with other fields on the span.

Proposal

This could look something like this for instance:

#[instrument(label = "params")]
fn foo(name: &str, target: &str) -> bool {
  // Do the foo things.
}

which would yield trace fields like params.name and params.target.

Alternatives

I don't believe there are any alternative solutions to this while using the #[instrument] attribute macro other than to explicitly skip_all and include the fields(...) with desired names.