mread:从一个绑定端口进行多次读取

轻便的epoll包装，用于读取多路插座 api // create a pool , listen on port , set max connection and , buffer size (0 for default 1M bytes) struct mread_pool * mread_create ( int port , int max , int buffer); // release the pool void mread_close ( struct mread_pool *m); // poll the poll, timeout (in milliseconds) can be -1 for indefinitely. // return id (which socket can read) , -1 for block int mread_poll ( struc