message: Don't clear summary FileWriterCache on each call to Estimator.fit().
diff: @@ -1034,7 +1034,6 @@ class BaseEstimator(
  loss = None
  while not mon_sess.should_stop():
  _, loss = mon_sess.run([model_fn_ops.train_op, model_fn_ops.loss])
  - core_summary.FileWriterCache.clear()
  return loss
  