title: FastAI V2: TabularLearner export.pkl from learn.export() is Very Large
body: <p>I'm not sure if this is intended but the <code>export.pkl</code> from the <code>learn.export()</code> is about 471 MB which is somewhat prohibitive in the deployment in certain applications.</p>
  <p>The model itself from <code>SaveModelCallback</code> is only <code>131 KB</code> and I'm only looking to use the <code>Learner</code> in order to apply the same transforms/processing (Normalization, FillMissing, Categorify).</p>
  <p>Is there a reason this is so large? I've also confirmed</p>
  <p><code>learn.xb</code> =
  (None, )</p>
  <p><code>learn.yb</code> =
  (None, )</p>