Function init_log 

pub fn init_log() -> Result<(), InitError>

Detect RAPX_LOG environment variable first; if it’s not set, default to INFO level.

Supported forms:

• RAPX_LOG=TRACE -> global level
• RAPX_LOG=some::module:DEBUG -> module level
• RAPX_LOG=TRACE,some::module:INFO,other::module:DEBUG -> mixed