rotating_file_handler.go
func (handler *RotatingFileHandler) Close() (err error) {
	handler.lock.Lock()
	err = handler.close()
	handler.lock.Unlock()
	return
}
func (handler *RotatingFileHandler) Close() (err error) {
	handler.lock.Lock()
	err = handler.close()
	handler.lock.Unlock()
	return
}
func ( handler * RotatingFileHandler ) Close ( ) ( err error ) { handler . lock . Lock ( ) err = handler . close ( ) handler . lock . Unlock ( ) return }
// Close releases resources used by this handler (file that log messages
// were written into).
Close releases resources used by this handler ( file that log messages were written into ) .