private void println(int logLevel, String format, Object... args) {
    if (logLevel < logConfiguration.logLevel) {
      return;
    }
    printlnInternal(logLevel, formatArgs(format, args));
  }
Print a log in a new line.

@param logLevel the log level of the printing log
@param format   the format of the printing log, null if just need to concat arguments
@param args     the arguments of the printing log
xlog/src/main/java/com/elvishew/xlog/Logger.java