# File lib/hiera/backend/yaml_backend.rb, line 65
      def stale?(yamlfile)
        # NOTE: The mtime change in a file MUST be > 1 second before being
        #       recognized as stale. File mtime changes within 1 second will
        #       not be recognized.
        stat    = File.stat(yamlfile)
        current = { 'inode' => stat.ino, 'mtime' => stat.mtime, 'size' => stat.size }
        return false if @cache[yamlfile] == current

        @cache[yamlfile] = current
        return true
      end