title: RxSwit - driver from observable ignoring errors
body: <p>Let's say I have some view initally filled with some data. Than I fetch data over network and want to update view with this updated data.</p>
  
  <p>At this point I want to create Driver from this observable to drive UI elements. However in case of error in observable I don't want to do anything, as the view has already some data so I just want to ignore such error. asDriver() function wants to define what should be done in case of error. Is it ok to do it like this:</p>
  
  <pre><code>let dataUpdated: Observable&lt;DataItem&gt; = ...
  
  let driver = dataUpdated.asDriver(onErrorDriveWith: Driver&lt;DataItem&gt;.empty())
  </code></pre>
  
  <p>?</p>