There's nothing super special about this design. It apparently uses a single "IO reactor" which handles readiness notifications for a couple of other threads. T

There's nothing super special about this design. It apparently uses a single "IO reactor" which handles readiness notifications for a couple of other threads. Those might be threadpool, and/or run non-blocking code (we don't know too much about this). This design is pretty much the same that you can e.g. find in the go runtime (netpoll), the .NET core runtime, Rust multithreaded async libraries, Java nio2, etc. The only thing that was special here is that they used an APC for waking up the reactor in case new events had to be added. Its non-standard, and kind of comparable to using a signal on unix to interrupt `select` instead of a message on a preregistered socket.