message: Updates the doc of SyncReplicasOptimizer. It notes that some worker can consume multiple mini-batches while some may not even one.
diff: @@ -78,7 +78,11 @@ class SyncReplicasOptimizer(optimizer.Optimizer):
  4. Only after all variables have been updated, increment the global step.
  5. Only after step 4, pushes `global_step` in the `token_queue`, once for
  each worker replica. The workers can now fetch the global step, use it to
  - update its local_step variable and start the next batch.
  + update its local_step variable and start the next batch. Please note that
  + some workers can consume multiple minibatches, while some may not consume
  + even one. This is because each worker fetches minibatches as long as
  + a token exists. If one worker is stuck for some reason and does not
  + consume a token, another worker can use it.
  For the replicas:
  