message: Optimize infeed pipeline by adding sharding and cache.
diff: @@ -117,6 +117,11 @@ class TPUContext(object):
  """The number of hosts for the TPU system."""
  return self._internal_ctx.num_hosts
  + @property
  + def current_host(self):
  + """The current host index for the TPU system."""
  + return self._invocation_index
  +
  @property
  def num_of_replicas_per_host(self):
  """The number of replicas for each host."""
  