Use native console levels.

[anp]

Allows using native devtools controls for choosing what shows up, inheriting coloring from levels.

Open questions:

• should this be another config flag instead of piggy-backing on the "use colors" flag? should it be the only option instead? (wasm-bindgen-test is rather unhappy with the css, i'll note)
• should the "native console" levels do anything different with TRACE level events? should the console include trace-level events at all?
• should the native console levels still include the level substring? most browsers do styling of those differently so we could maybe save some horizontal space by omitting them (as it is in this PR)

[colelawrence]

Thanks for the added thoughts, @anp.

There have been several suggestions for adding higher customizability at this point (like in #3).

I'm almost wondering if we should open up the API to be much more customizable through things like allowing you to replace the default formatter (like a FnMut(EventInfo) -> Vec<String> :: event info -> console arguments), replace the default performance API caller, etc.

What do you think?

[colelawrence]

Super cool addition, by the way! I think this makes a lot of sense, I may add a configuration for this behavior to opt-out.

[anp]

Makes sense, yeah. What do you think about setting things up as Layers?

Splitting the one layer into PerformanceLayer and ConsoleLayer would make it easy to have different initialization mechanisms. You could maybe have a PerformanceLayer::from_global() and a PerformanceLayer::from_instance(p: js_sys::...)? Similarly there could be ConsoleLayer::info() and ConsoleLayer::with_native_levels(). Or perhaps builders for the layers?

You could still have convenience functions like set_as_global_default on top of course.

[anp]

And yeah I think that having progressive levels of customization is very valuable and in line with tracing's philosophy AFAICT.

[colelawrence]

@anp, awesome suggestion! I really like the idea of splitting them up as layers, and having a default set of layers for different environments.

I can look at doing this next week.

[colelawrence]

Above here, it looks like we could still wire up log4, info4, debug4, etc

[colelawrence]

Notes for the future: if this is continued to be implemented, I would like it to be guarded by a config option