class_docstr: This class represents a reference of a workflow output.
  
  A reference means the workflow has already been executed,
  and we have both the workflow task ID and the object ref to it
  living outputs.
  
  This could be used when you want to return a running workflow
  from a workflow task. For example, the remaining workflows
  returned by 'workflow.wait' contains a static ref to these
  pending workflows.
code: def __hash__(self):
      return hash(self.task_id)
  
imports: import base64
  import json
  from ray import cloudpickle
  from enum import Enum, unique
  import hashlib
  from typing import Dict, Optional, Any, Tuple
  from dataclasses import dataclass
  import ray
  from ray import ObjectRef
  from ray._private.utils import get_or_create_event_loop
  from ray.util.annotations import PublicAPI
label_desc: Use image node_id 2 for calling the WorkflowRef obj's underlying member method code with example usage: obj.__hash__() and returns: hash