title: Trying to understand subscribeActual()
body: <p><a href="https://stackoverflow.com/questions/44714124/rxjava-2-0-what-is-the-difference-between-observable-subscribe-and-observable-su">This question</a> asks what I want to know, but the answer doesn't explain it. Could someone share a concrete example that illustrates how to use <code>subscribeActual()</code> vs. <code>subscribe()</code>? </p>