title: tf.data.Dataset - delete cache?
body: <p>Is it possible to delete the in-memory cache that's built after calling <code>tf.data.Dataset.cache()</code>?</p>
  <p>Here's what I'd like to do. The augmentation for the dataset is very costly, so the current code is more or less:</p>
  <pre class="lang-py prettyprint-override"><code>data = tf.data.Dataset(...) \
         .map(&lt;expensive_augmentation&gt;) \
         .cache() \
         # .shuffle().batch() etc. 
  </code></pre>
  <p>However, this means that every iteration over <code>data</code> will see the same augmented versions of the data samples. What I'd like to do instead is to use the cache for a couple of epochs and then start over, or equivalently do something like <code>Dataset.map(&lt;augmentation&gt;).fleeting_cache().repeat(8)</code>. Is this possible to achieve?</p>