the core loge code (extract from my uvx project)

loge is a logging protocol focus on encoding log items.

Initially, I wrote these code in uvx[1]. And now, loge itself is an independent project. uvx still use loge to implement uvx_log_t. There will be other logging implementions based on loge. (uvx_log_t is not the only one, and not the best one.)

1: https://github.com/liigo/uvx