红鸟Sessions类php环境，用mysql数据库接管原来由文件系统支撑的php session，解决了session兼容性、虚拟主机无法自定义session等问题，内置gc函数，可以按概率触发删除过期session。在php原始session用法不变的情况下，提高了原有session的性能。-Red Bird Sessions class php environment, using mysql database to take over the original file system supported by the php session, to solve the session compatibility, virtual host can not customize the session and other issues, built-in gc function, you can press the probability of triggering delete expired session. In php original session under the same usage, improve the performance of the original session.