一个重叠I/O串口类,用windows API实现，封装了打开串口、设置串口波特率、缓存、用重叠I/O发送、接收等功能。-A duplication of I/O serial type, the windows API to achieve, a package to open serial port, serial port baud rate settings, cache, and overlapping I/O to send, receive functions.