title: Equivalent of RxJS switchMap in ReactiveX/Rx.NET
body: <p>In <strong>RxJS</strong>, there is a <a href="https://www.learnrxjs.io/operators/transformation/switchmap.html" rel="noreferrer">switchMap</a> function. Is there an equivalent in <strong>ReactiveX/Rx.NET</strong>? I don't see one in the <a href="http://reactivex.io/documentation/operators.html#transforming" rel="noreferrer">transforming</a> documentation.</p>