message: Add documentation to clarify that intermediate tensors of `tf.cond` branches must not be directly accessed but rather returned as branch function outputs.
diff: @@ -2124,6 +2124,12 @@ def cond_for_tf_v2(pred, true_fn=None, false_fn=None, name=None):
  Singleton lists and tuples form the only exceptions to this: when returned by
  `true_fn` and/or `false_fn`, they are implicitly unpacked to single values.
  + Note: It is illegal to "directly" use tensors created inside a cond branch
  + outside it, e.g. by storing a reference to a branch tensor in the python
  + state. If you need to use a tensor created in a branch function you should
  + return it as an output of the branch function and use the output from
  + `tf.cond` instead.
  +
  Args:
  pred: A scalar determining whether to return the result of `true_fn` or
  `false_fn`.
  