This proposal adds task-local logger storage so that metadata can accumulate across async
call stacks without threading a Logger through every function signature.

Motivation:

Metadata propagation requires threading a logger through every layer. Every function on
the path from request ingress to the bottom of the call stack has to accept, mutate, and
forward a Logger. Libraries must choose between polluting their public API with a logger: parameter and
losing all the caller's context. There is no third option today.

Modifications:

• New API surface for reading and modifying the @TaskLocal Logger instance added.
• Best practices on how to correctly propagate logger into libraries updated with Logger.current API.

Result:

Users can now automatically propagate accumulated metadata into libraries without explicitly passing loggers through the API boundaries.