fix(logger): print to stderr if log fails for default format

[nickajacks1]

Description

We log to stderr if logging fails when a custom format is used, but not for the default format. This change addresses this inconsistency.

Type of Change

Please delete options that are not relevant.

• Enhancement (improvement to existing features and functionality)
• Code consistency (non-breaking change which improves code reliability and robustness)

Checklist

Before you submit your pull request, please make sure you meet these requirements:

• Conducted a self-review of the code and provided comments for complex or critical parts.
• Ensured that new and existing unit tests pass locally with the changes.

[nickajacks1]

One other thing I noticed was that the log write is only protected by a mutex lock when the non-default format is used. Perhaps we should be locking in both places...?

[efectn]

One other thing I noticed was that the log write is only protected by a mutex lock when the non-default format is used. Perhaps we should be locking in both places...?

There should not be issue when writing logs to a file using POSIX write() or stdout. But there are probably some edge cases that may cause data races. So i'd be OK to add mutex both places.

[nickajacks1]

Thought about the locking some more. It's probably not a good idea for fiber to add locking. Since os.File operations are goroutine safe, and since I'm sure >99% of cases will be logging to os.File, it's probably better to have users implement locking in their Write methods. Either way, I'll follow up with a separate PR later.