title: Passing two evaluation datasets to HuggingFace Trainer objects
body: <p>Is there any ways to pass two evaluation datasets to a HuggingFace Trainer object so that the trained model can be evaluated on two different sets (say in-distribution and out-of-distribution sets) during training? Here is the instantiation of the object, which accepts just one <code>eval_dataset</code>:</p>
  <pre><code>trainer = Trainer(
      model,
      args,
      train_dataset=train_dataset,
      eval_dataset=eval_dataset,
      tokenizer=tokenizer
  )
  </code></pre>