• bom : utf8
• CODE_POINT_MAX : utf8::internal
• LEAD_OFFSET : utf8::internal
• LEAD_SURROGATE_MAX : utf8::internal
• LEAD_SURROGATE_MIN : utf8::internal
• SURROGATE_OFFSET : utf8::internal
• TRAIL_SURROGATE_MAX : utf8::internal
• TRAIL_SURROGATE_MIN : utf8::internal