Add a debugging reporter to the new resolver

[pradyunsg]

🌈

This is obviously not optimized and will make log files a bit bigger, but any opinions against this (given that we're not printing the "state" table)?

[uranusjr]

Looks good for me.

[pfmoore]

Maybe only install the reporter if the logging level indicates it's needed? Would that make a difference in performance? I'm a little worried about introducing unnecessary overhead when people are already complaining about speed.

But otherwise this LGTM

[pradyunsg]

Ah mypy. :)

[uranusjr]

Maybe only install the reporter if the logging level indicates it's needed? Would that make a difference in performance?

Good idea IMO. The logging module is known to be slow.

[pradyunsg]

Closing since #9017 adds a reporter, and adding this would cause merge conflicts that I don't wanna deal with. :)