></pre>
<p>This ability - lazily define a column via interface implementation and still
efficiently operate on that column - separates the implementation of
the <code>tech.ml.dataset</code> library from other libraries in this field.  This is likely
to have an interesting and different set of advantages and disadvantages that will
present themselves over time.  The dataset library is very loosely bound to the
underlying data representation allowing it to represent data that is much larger
than can fit in me