class_docstr: A blocking operator that executes once its inputs are complete.
  
  This operator implements distributed sort / shuffle operations, etc.
code: def num_outputs_total(self) -> int:
      return (
          self._num_outputs
          if self._num_outputs
          else self.input_dependencies[0].num_outputs_total()
      )
  
imports: from typing import List, Optional
  from ray.data._internal.execution.interfaces import AllToAllTransformFn, PhysicalOperator, RefBundle, TaskContext
  from ray.data._internal.logical.interfaces import LogicalOperator
  from ray.data._internal.progress_bar import ProgressBar
  from ray.data._internal.stats import StatsDict
label_desc: Use image node_id 2 for calling the AllToAllOperator obj's underlying member method code with example usage: obj.num_outputs_total() and returns: unknown