code: public static final double getDoubleAttribute(Path path, String attribute, LinkOption... options) throws IOException
      {
          return getDoubleAttribute(path, attribute, Double.NaN, options);
      }
docs: Returns user-defined-attribute NaN if not found.
  @param path
  @param attribute
  @param options
  @return
  @throws IOException
  @see java.lang.Double#NaN