title: Does map()/mapPartition() output record count should be matching with input record count?
body: <p>If I have a dataset of 100 records partitioned into 10 partitions and if I run mapPartition function over it, does the output dataset size has to be 100? Or can I have more than 100 records in it? (like flatmap)
  Sample code : </p>
  
  <pre><code>Dataset&lt;Ledger&gt; ledger = balance.mapPartitions(new customTransformationFunction(config)),
                  Encoders.bean(Ledger.class));
  </code></pre>
  
  <p>Can the size of ledger dataset be more than 100?</p>