Configure worker thread name in tracing-appender

Crates

tracing-appender

Motivation

In v0.3.16, the worker thread does not have a proper name, so it takes the application's name. In master, it seems it uses "tracing-appender". It is useful to quickly identify threads for auditing or affinity pinning.

Proposal

Add a field to NonBlockingBuilder with a setter. Pass this name during worker init.