code: func (logger *Logger) SetFormatter(formatter lg.Formatter) {
  	unsafeStd := (*unsafe.Pointer)(unsafe.Pointer(&logger.std))
  	old := logger.std
  	logger.std.Formatter = formatter
  	atomic.CompareAndSwapPointer(unsafeStd, unsafe.Pointer(old), unsafe.Pointer(logger.std))
  }
docs: // SetFormatter sets the standard logger formatter.