*   Renames `experimental_hints` in
        `tf.distribute.StrategyExtended.reduce_to`,
        `tf.distribute.StrategyExtended.batch_reduce_to`,
        `tf.distribute.ReplicaContext.all_reduce` to `options`.
    *   Renames `tf.distribute.experimental.CollectiveHints` to
        `tf.distribute.experimental.CommunicationOptions`.
    *   Renames `tf.distribute.experimental.CollectiveCommunication` to

		{"RegEnumKeyEx", Func, 0},
		{"RegOpenKeyEx", Func, 0},
		{"RegQueryInfoKey", Func, 0},
		{"RegQueryValueEx", Func, 0},
		{"RemoveDirectory", Func, 0},
		{"Removexattr", Func, 1},
		{"Rename", Func, 0},
		{"Renameat", Func, 0},
		{"Revoke", Func, 0},
		{"Rlimit", Type, 0},
		{"Rlimit.Cur", Field, 0},
		{"Rlimit.Max", Field, 0},
		{"Rmdir", Func, 0},
		{"RouteMessage", Type, 0},

  let summary = [{
V2 format specific: merges the metadata files of sharded checkpoints.  The
  }];

  let description = [{
result is one logical checkpoint, with one physical metadata file and renamed
data files.

Intended for "grouping" multiple checkpoints in a sharded checkpoint setup.

If delete_old_dirs is true, attempts to delete recursively the dirname of each