Reduce log level used by tracing instrumentation from info to debug

[tmiasko]

Restore log level to debug to avoid make info log level overly verbose (the uses of instrument attribute modified there, were for the most part a replacement for debug!; one use was novel).

[nagisa]

Could the description and/or the commit message be adjusted to include a few sentences outlining the rationale?

[oli-obk]

is there a way to set the default #[instrument] log level (maybe via a tracing crate feature or sth)?

[tmiasko]

I think it is impossible to change the default currently.

[oli-obk]

Ok, then let's do this.

One rationale could be to not have these spans in the regular rustc, but only in the debug-assertions version

[lcnr]

@bors r+ rollup

I think it is impossible to change the default currently.

I don't know much about tracing but would it make sense to open an issue about this? I think having instrument default to debug makes sense for rustc.

[bors]

📌 Commit 59457ab has been approved by lcnr

[oli-obk]

Tracing 0.2 will remove the default and require a specification of the level for every use of the macro: tokio-rs/tracing#1122

[Mark-Simulacrum]

@bors rollup=never - I'm worried this could have perf implications

[bors]

⌛ Testing commit 59457ab with merge 26e5bcd...

[bors]

☀️ Test successful - checks-actions
Approved by: lcnr
Pushing 26e5bcd to master...