先来张总体架构图吧，从官网拿的，根据这个图来分析下
A worker represents a mediasoup C++ subprocess that runs in a single CPU core and handles Router instances.
可以看到每个worker相当于一个sfu，核心转发逻辑是router，下面我们来分析下这个router
A router enables injection, selection and forwarding of media streams through Transport instances created on it.
router维护了订阅关系：mapProducerConsumer。当producer有数据过来会直接转发给订阅它的consumer