code: public static <D extends DifferenceEngineConfigurer<D>>
          D withPlaceholderSupportUsingDelimiters(D configurer, String placeholderOpeningDelimiterRegex,
              String placeholderClosingDelimiterRegex) {
          return configurer.withDifferenceEvaluator(new PlaceholderDifferenceEvaluator(placeholderOpeningDelimiterRegex,
              placeholderClosingDelimiterRegex));
      }
docs: Adds placeholder support to a {@link DifferenceEngineConfigurer}.
  @param configurer the configurer to add support to
  @param placeholderOpeningDelimiterRegex regular expression for
  the opening delimiter of placeholder, defaults to {@link
  PlaceholderDifferenceEvaluator#PLACEHOLDER_DEFAULT_OPENING_DELIMITER_REGEX}
  if the parameter is null or blank
  @param placeholderClosingDelimiterRegex regular expression for
  the closing delimiter of placeholder, defaults to {@link
  PlaceholderDifferenceEvaluator#PLACEHOLDER_DEFAULT_CLOSING_DELIMITER_REGEX}
  if the parameter is null or blank
  @return the configurer with placeholder support added in