code: private void println(int logLevel, String msg, Throwable tr) {
      if (logLevel < logConfiguration.logLevel) {
        return;
      }
      printlnInternal(logLevel, ((msg == null || msg.length() == 0)
          ? "" : (msg + SystemCompat.lineSeparator))
          + logConfiguration.throwableFormatter.format(tr));
    }
docs: Print a log in a new line.
  
  @param logLevel the log level of the printing log
  @param msg      the message you would like to log
  @param tr       a throwable object to log