title: Rx subscriptions and garbage collection
body: <p>Do you need to assign the IDisposable returned by <code>IObservable.Subscribe</code> to a variable in order to protect the subscription from being garbage collected, or is the presence of an active subscription enough?</p>
  
  <p>My use case: I create a one-shot observable from an existing observable (<code>myObservable</code> in the example):</p>
  
  <pre><code>myObservable.Take(1).Subscribe(fun v -&gt; printfn "One-shot: %A" v) |&gt; ignore
  </code></pre>