message: Document explicitly `iterations_per_loop` is not respected in TPUEstimator evaluation.
diff: @@ -62,6 +62,8 @@ class TPUConfig(
  system before returning to CPU host for each `Session.run`. This means
  global step is increased `iterations_per_loop` times in one `Session.run`.
  It is recommended to be set as number of global steps for next checkpoint.
  + Note that in evaluation don't use this value, instead we run total eval
  + `steps` on TPU for a single `Session.run`.
  num_shards: (Deprecated, ignored by TPUEstimator).
  The number of model replicas in the system. For non-model-parallelism
  case, this number equals the total number of TPU cores. For
  