Performance of Sampled Datra Systems

What is the steady-state step response of a SD system where the SD system is closed-loop stable and $T>0$ is non-pathological?

Theorem

If $T>0$ is non-pathological and the SD system is closed-loop stable. Let $r(t)=1(t)$. Then $y_{ss}={\lim }_{t\to \infty }=T_{ry}[1]$.