if err != nil && !os.IsNotExist(err) { // If it's other errors, it should be logged at here (debug level).
			c.logger.Debug(
				"Failed to read existing CNI configuration file",
				logfields.Error, err,
				logfields.Destination, dest,
			)
		}
		if err := renameio.WriteFile(dest, contents, 0600); err != nil { // If write failed, will return error, will not go to the following code; If no error, the err variable is shadowed, the following err variable will use the previous err variable.
			return fmt.Errorf("failed to write CNI configuration file at %s: %w", dest, err)
		}
		c.logger.Info(
			"Wrote CNI configuration file",
			logfields.Error, err, // Error here must be the NotExist error (usually startup first time), it's meaningless, may even be misleading, should be removed
			logfields.Destination, dest,
		)