title: Do I have to explicitly use Dataframe's methods to take advantage of Dataset's optimization?
body: <p>To take advantage of <code>Dataset</code>'s optimization, do I have to explicitly use <code>Dataframe's</code> methods (e.g. <code>df.select(col("name"), col("age")</code>, etc) or calling <strong><em>any</em></strong> Dataset's methods - <strong><em>even RDD-like methods</em></strong> (e.g. <code>filter</code>, <code>map</code>, etc) would also allow for optimization?</p>