实现基于声卡的多路音频实时采集，独立的线程处理

本源代码功能，从udp socket 接收音频，然后通过声卡播放。可同时接收和播放多路音频。代码中有udp socket组播的编程，线程池的编程例子，音频播放的编程。-Source code function, receiving audio from udp socket, and then played through the sound card. Can receive and play multi-channel audio. Code has multicast udp socket