message: Add a single capacity prefetch to `tf.contrib.data.read_batch_features`.
diff: @@ -179,6 +179,7 @@ def read_batch_features(file_pattern,
  dataset = dataset.shuffle(capacity)
  dataset = dataset.batch(batch_size)
  dataset = dataset.map(lambda x: parsing_ops.parse_example(x, features))
  + dataset = dataset.prefetch(1)
  iterator = dataset.make_one_shot_iterator()
  outputs = iterator.get_next()
  return outputs
  