error exception util: 1. add logging() 2. explicitly make Guarantor non-movable 3. special current_value process for wide-char
error exception util:
1. add logging()
2. explicitly make Guarantor non-movable
3. special current_value process for wide-char

kingsamchen/KBase_Demo,kingsamchen/KBase_Demo,kingsamchen/KBase,kingsamchen/KBase