This page describes Tufão's design model.

Just like Node.JS, Tufão uses an async event-driven model. That is, Tufão will handle multiple connections per thread. The Qt executor (i.e. QCoreApplication, QThread or other) will take care of the scheduling tasks required to handle multiple connections per thread. You can also spawn multiple executors in different threads and delegate different handlers to different executors, then you'll have a multiple-connections-per-event-loop/one-event-loop-per-thread architecture.

The server will begin to work once the control goes to the Qt executor (e.g. QCoreApplication::exec).

The simplest choice is just to use single-threaded async I/O.