Initial release, slog, zap, fortio log

What's Changed

• Initial version with fortio logger by @ldemailly in #2
• Zap version by @ldemailly in #3
• Added slog initial by @ldemailly in #4
• Comparison, adding memory stats and optional -profile + fixes by @ldemailly in #5

Full Changelog: https://github.com/fortio/logger-bench/commits/v0.1.0