code: CssReader forward(CharMatcher matcher) throws
        IOException
    {
      while (true)
      {
        Mark mark = mark();
        next();
        //TODO escape awareness
        if (curChar == -1 || (matcher.matches((char) curChar) && prevChar != '\\'))
        {
          unread(curChar, mark);
          break;
        }
      }
      return this;
    }
docs: Read forward until the next non-escaped character matches the given
  CharMatcher or is EOF.
  
  @throws IOException