unix或者linux下app写日志文件，多线程安全写日志记录，使用方便。-unix or linux to write the log files under the app, multi-thread-safe to write log records, easy to use.

unix-linux下多功能定时器，可以有多个alarm，线程安全。-unix-linux under the multi-function timer, you can have more than one alarm, thread-safe.