Function encode_log 

pub fn encode_log(text: &[u8], out: &mut [u8; 253]) -> usize

Encode one log copy. Text past LOG_TEXT_MAX bytes is cut HERE, at that byte count and not at a character boundary, so a clipped copy can end mid-character. (This said the CALLER truncated at a char boundary; ServiceContext::log_copy passes the text through unclipped.)