code: public static ParseException withStartPosition(
        String errorMessage, String logMessage, int start) {
      return new ParseException(msg(errorMessage, logMessage, start, -1), logMessage);
    }
docs: Creates a new parse exception for situations in which only the start position of the error is
  known.
  
  @param errorMessage the user error message.
  @param logMessage the original log message.
  @param start the index of the first character in the invalid section of the log message.
  @return the parser exception.