If the request/response handlers are much slower (large computation or IO) than the connection acceptor, the acceptor will necessarily be slowed to the rate of

If the request/response handlers are much slower (large computation or IO) than the connection acceptor, the acceptor will necessarily be slowed to the rate of your handlers, limiting the number of connections you can accept. Also, connection acception and request/response handling are two logically separate things, which are always nice to keep separate when possible.