code: @Override
      public String tagValue(String value) {
          String sanitized = delegate.tagValue(value);
          return StringEscapeUtils.escapeJson(sanitized.endsWith("\\") ?
                  sanitized.substring(0, sanitized.length() - 1) + "_" :
                  sanitized);
      }
docs: We recommend enclosing tag values with double quotes (" "). If you surround the value with quotes any character is allowed,
  including spaces. To include a double quote, escape it with a backslash. The backslash cannot
  be the last character in the tag value.